3 questions concerning calibration procedures with spyder express/ 2suite/ pro
2006-04-22 by esimanor
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2006-04-22 by esimanor
1.Do you know if one could possibly update software at later stage from Spyder Express to say Syder 2 Suite or even Spyder pro since it seems as if all use the same spyder device? 2.Can one select "Native" gamma and white point temperature using Spyder 2 Suite or spyder Pro software/ 3.can one manually select his own white and black point luminance settings in the calibartion process using Spyder express? what about spyder Pro?
2006-04-22 by John Vitollo
--- In colorvision_group@yahoogroups.com, "esimanor" <esimanor@...> wrote: > 2.Can one select "Native" gamma and white point temperature using > Spyder 2 Suite or spyder Pro software/ I'm using Spyder2PRO...only "Native" white point temp can be selected. No settings for native gamma. This is with a Dell 1905FP LCD. > 3.can one manually select his own white and black point luminance > settings in the calibartion process using Spyder express? what about > spyder Pro? With the Spyder2PRO manually inputing White Luminance values works fine...but the Black Luminance seems to be anchored at 0.30. I've tried to change the value but stays at 0.30
2006-04-22 by esimanor
> Luminance seems to be anchored at 0.30. I've tried to change the value but stays at 0.30 > Thanks for all this Do we know what unit is being used for luminance (0.30 for blacks)? How does it relate to grey scale? How do you set your brightness and contrast screen adjustments before starting calibration procedure?
2006-04-22 by CDTobie@aol.com
2006-04-22 by CDTobie@aol.com
2006-04-22 by CDTobie@aol.com
2006-04-23 by John Vitollo
> > the Black Luminance seems to be anchored at 0.30. I've tried to > > change the value but stays at 0.30 > Its adjustable: try raising it. You can't set it lower than the native black > of your monitor, which may be what had you stumped. > C. David Tobie I tried going higher to 0.40 and lower to 0.20...but value sticks at 0.30. I can set White Luminance with no problem. Using Spyder2PRO Version 2.2-4
2006-04-23 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > You are told to set them to factory defaults; if you don't have a reset > control, I would recommend 50 percent contrast and 100 percent brightness as > starting values. Thanks a lot for all that. But here is a crucial issue, I think: i am glad to read that there is such a thing as a standard luminance unit (candela). But how on earth do your Brightness and Contrast adjustments on your screen relate to this?? Is there any clear corellation between 1% change in Brightness and the increase of your black point by such and such candelas?! what about contrast? Plus here is another critical point: what exactly is your Brightness and your Contrast adjustment knobs doing to your black and white point on an LCD screen? I read somewhere that an LCD can only offer one adjustment, which is the backlight of the display (most likely to affect only your black level (brightness?), I would have thought)?... Now, the factory settings on my LCD (NEC multisync 1980 FXi) are as assumed Brightness: 100% and Contrast: 50% but this gives a very high black level indeed (too high )! Plus, i work with agencies in europe to whom I send processed files. most of these agencies still use CRT's which tend to be naturaly "darker" than LCD's. Could i possibly ask them to measure the luminance of there black and white point and try to "copy" them on my screen before calibrating? how would i go about this? Ideally they would provide me with a measure in candela for each point and i would feed it to my software, or I would be able to establish a corellation between the candela values and my settings?...
2006-04-23 by CDTobie@aol.com
2006-04-23 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > Does it matter? Does it matter to adjust your gamma and your white point temperature to given values? just tweak them until the result seems pleasing to your eyes and that's it... but if you want to get any close to see your files on your screen more or less as your client will see them on his screen (provided you work with more or less the same ambiant light, which can be achieved), with similar shadows, mid tones and highlights, then you need to achieve similar luminance display target. Or does that not make any sense? You adjust the controls, the Spyder reads the results. When > you have gotten as close Close to WHAT? as your controls can manage, you stop tweaking, and
> move on. > > C. David Tobie > Product Technology Manager > ColorVision Business Division > DataColor Inc. > CDTobie@... > www.colorvision.com >
2006-04-23 by CDTobie@aol.com
2006-04-23 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > To the target values you specified when you began. If your target black > luminance is set to .4, then the software will assist you in adjusting to that. Of > course, if your monitor's native blackpoitn is .6, and you chose .4 because it > sounded better to you, there is no way you will be able to lower the > blackpoint, so you will fail to reach that target, just as asking for a black darker > than what your printer, inks, and paper can manage is not possible. > > For white, I would recommend you use the ambient light function of Spyder2PRO > v2.2, and choose an appropriate white luminance value for your situation, > instead of simply running your monitor at max luminance, which may be way off for > your lighting (causing poor matching), not to mention burning your monitor > out faster than necessary. White is very relative (as the eye is very > adjustable), and unless monitors are side by side, setting them to the same white > luminance is not necessary (or desirable), while setting them to appropriate white > luminance for your environment is very necessary. All this makes perfect sens, thank you I wonder, though, if using your eye, under ambiant light, to determine the "right" black and white point luminances isn't even better than using software since these are such subjective notions. But then again: the two "knobs" available on most LCD screens (brightness and contrast) are not readily helpful for that... Not clear neither on which kind of chart this should be done.
2006-04-24 by Brian Smith
--- In colorvision_group@yahoogroups.com, "esimanor" <esimanor@...> wrote: > > But here is a crucial issue, I think: > > i am glad to read that there is such a thing as a standard luminance > unit (candela). But how on earth do your Brightness and Contrast > adjustments on your screen relate to this?? Is there any clear > corellation between 1% change in Brightness and the increase of your > black point by such and such candelas?! what about contrast? > > Plus here is another critical point: what exactly is your Brightness > and your Contrast adjustment knobs doing to your black and white > point on an LCD screen? I read somewhere that an LCD can only offer > one adjustment, which is the backlight of the display (most likely to > affect only your black level (brightness?), I would have thought)?. .. > > Now, the factory settings on my LCD (NEC multisync 1980 FXi) are > as assumed Brightness: 100% and Contrast: 50% but this gives a very > high black level indeed (too high )! Plus, i work with agencies in > europe to whom I send processed files. most of these agencies still > use CRT's which tend to be naturaly "darker" than LCD's. Could i > possibly ask them to measure the luminance of there black and white > point and try to "copy" them on my screen before calibrating? how > would i go about this? Ideally they would provide me with a measure > in candela for each point and i would feed it to my software, or I > would be able to establish a corellation between the candela values > and my settings?... > I may be completely wrong here but I think you are getting the wrong end of the stick about the purpose of this device. I don't think it is ever intended to match the illumination levels between monitors or any other viewing system, just give the same appearance of colour. Also I think you have the terms a little mixed up. My understanding of brightness, as a control, is that it adds or subtracts a constant value from the value of each pixel but the overall luminance of a pixel depends on the source of the light, be it backlight, CRT phosphor, or 10kW projector lamp. Contrast, as a control, affects the steepness of the curve that relates pixel values to screen brightness values. It should not affect the black or white point. Again, I may be completely wrong, but I think it is unreasonable to expect to match the actual illumination levels of your monitor and your client's. All you can expect to do is both be able to see the same shadow and highlight detail and perceive the same colours. Presumably your client's screen is not the end use for your images. If they are going to be ending up as print then the illumination levels are meaningless anyway.
2006-04-24 by CDTobie@aol.com
2006-04-24 by CDTobie@aol.com
2006-04-25 by John Vitollo
>I just ran this app, and when I defined a new target, it offered me blank values for both white and black luminance If I define a new target the values are filled with the current settings. I then change both values and the new White Luminance value is updated in the "Current Settings" window but the Black Luminance value goes back to 0.30. Same if I try to change the current settings using "Change these settings" and click through the Next button.... Thanks! Using Spyder2PRO Version 2.2-4 Mac 10.4.6 On 4/24/06 7:54 PM, "CDTobie@..." <CDTobie@...> wrote: In a message dated 4/22/06 10:29:29 PM, jvlist@... writes: I tried going higher to 0.40 and lower to 0.20...but value sticks at 0.30. I can set White Luminance with no problem. Using Spyder2PRO Version 2.2-4 I just ran this app, and when I defined a new target, it offered me blank values for both white and black luminance, though it would fill them in later for me if I left them blank. At what point are you expecting to be able to change them, that you can't? I suspect this is not a bug, but a user expectation issue... C. David Tobie
2006-04-25 by CDTobie@aol.com
2006-04-25 by esimanor
--- In colorvision_group@yahoogroups.com, "Brian Smith" <zen1@...> wrote: > I may be completely wrong here but I think you are getting the wrong > end of the stick about the purpose of this device. I don't think it is > ever intended to match the illumination levels between monitors or any > other viewing system, just give the same appearance of colour. Also I > think you have the terms a little mixed up. My understanding of > brightness, as a control, is that it adds or subtracts a constant > value from the value of each pixel but the overall luminance of a > pixel depends on the source of the light, be it backlight, CRT > phosphor, or 10kW projector lamp. Contrast, as a control, affects the > steepness of the curve that relates pixel values to screen brightness > values. It should not affect the black or white point. If contrast was to control that curve then it should be called Gamma, really.... no? The terms brightness and contrast are confusing, even more when they relate to an LCD display. Strictly speaking and since the luminance of your display depends partly on your own subjective assesment and partly on the amount of ambiant light, these two "knobs" are there to allow you to set your pedestal (black level, usualy called brightness) and your white point luminance (usualy called contrast). This rule applies well on a CRT, as for LCD's I am not so sure. > > Again, I may be completely wrong, but I think it is unreasonable to > expect to match the actual illumination levels of your monitor and > your client's. All you can expect to do is both be able to see the > same shadow and highlight detail and perceive the same colours. If you can adjust for same shadows and highlights and if you are set up for similar gamma, then you will see roughly the same thing, I am pretty sure. > Presumably your client's screen is not the end use for your images. If > they are going to be ending up as print then the illumination levels > are meaningless anyway. Well this is true but if you adjust your pictures for a screen whose over all luminance is widely different from the one on which your pictures will be seen then your pictures will appear widely too bright or dark on that same display, which indeed does not imply anything as for further uses. >
2006-04-25 by Brian Smith
--- In colorvision_group@yahoogroups.com, "esimanor" <esimanor@...> wrote: > > If contrast was to control that curve then it should be called Gamma, > really.... no? > The terms brightness and contrast are confusing, even more when they > relate to an LCD display. Strictly speaking and since the luminance > of your display depends partly on your own subjective assesment and > partly on the amount of ambiant light, these two "knobs" are there to > allow you to set your pedestal (black level, usualy called > brightness) and your white point luminance (usualy called contrast). > This rule applies well on a CRT, as for LCD's I am not so sure. In truth I am right and you are partly right. When adjusting the contrast of a photographic image you adjust the centre of an S curve but the curve in question, the contrast on a CRT or LCD, is a straight line and so adjusting the contrast of an image with a fixed black point does indeed affect the luminance of white. Contrast is definitely not gamma. Gamma is a curve that corrects linear digital images to account for the non linearity of visual perception. In fact the term I think originated in the compensation applied to the analogue video signal driving the grid of CRT's to correct for the non linear transfer function between grid voltage and anode current. This of course is long before the days of computer monitors. > > > Presumably your client's screen is not the end use for your images. > If > > they are going to be ending up as print then the illumination > levels > > are meaningless anyway. > > Well this is true but if you adjust your pictures for a screen whose > over all luminance is widely different from the one on which your > pictures will be seen then your pictures will appear widely too > bright or dark on that same display, which indeed does not imply > anything as for further uses. I don't believe that an observer is capable of making absolute luminance judgements. The contrast should be adjusted for the comfort of the viewer and to keep the CRT or LCD within it's linear range of reproduction. You may not realise it but if you try to drive your CRT too hard to get a bright picture in a room of high illumination current limiter circuits in the monitor will act to limit the brightness and protect the tube. When that happens it will affect the accuracy of the image. All you should have to do in profiling your display is accurately reproduce colour and greyscale divisions and make sure that all gradations between black and maximum white are discernable. The Spyder can do that.
2006-04-26 by esimanor
--- In colorvision_group@yahoogroups.com, "Brian Smith" <zen1@...> wrote: > > Contrast is definitely not gamma. Oh Yes! Gamma and Contrast are intricately linked. Your display (any display) has got a native gamma that describes the way it is reacting to incoming signal. The software gamma that is applied to a signal supposed to be shown on that display is there to compensate for the non linear gamma curve of the display that would otherwise alter the "natural" contrasts of your picture Now again, the confusion comes from the use of the wrong terminology for the two tweaking knobs on your display: "brightness" and "contrast". As said before, "brightness" relates to black level (and as such it will have a direct influence on the contrast of the picture). "Contrast" is brightning or darkening your white point hence it is having an influence on the overall brightness of the picture which shows the non sense in the choice of terminology... > I don't believe that an observer is capable of making absolute > luminance judgements. Of course not, since luminance judgement is subjective and varies from one viewer to the other and with ambiant light. Which is why I don't quite see the use of being able to set your black and white point luminance value in Candela unit in the Spyder Pro software version. How do these candela setting relates to the viewer assesment of display luminance? >The contrast should be adjusted for the comfort Yes but again, it is not the contrast that has to be adjusted for comfort, it is the pedestal and the white point luminance
2006-04-26 by Tom
--- In colorvision_group@yahoogroups.com, "esimanor" <esimanor@...> wrote: > Of course not, since luminance judgement is subjective and varies > from one viewer to the other and with ambiant light. Which is why I > don't quite see the use of being able to set your black and white > point luminance value in Candela unit in the Spyder Pro software > version. How do these candela setting relates to the viewer assesment > of display luminance? Its useful if you want to get side by side display units looking exactly the same.
2006-04-26 by esimanor
--- In colorvision_group@yahoogroups.com, "Tom" <ttrostel@...> wrote: > How do these candela setting relates to the viewer assesment > > of display luminance? > > Its useful if you want to get side by side display units looking > exactly the same. Yes but how does one know how to relate between a setting in Candela and the actual luminance level it will yield to the eye of the viewer? Plus how do you take into account the level of ambiant light if what you want is to achieve is respectively a given black and white point luminance?
2006-04-26 by CDTobie@aol.com
2006-04-26 by Brian Smith
--- In colorvision_group@yahoogroups.com, "esimanor" <esimanor@...> wrote: > > --- In colorvision_group@yahoogroups.com, "Brian Smith" <zen1@> > wrote: > > > > Contrast is definitely not gamma. > > Oh Yes! Gamma and Contrast are intricately linked. Your display (any > display) has got a native gamma that describes the way it is reacting They may be linked but they adjust the response curve in different ways. Contrast is a purely linear adjustment. > > Now again, the confusion comes from the use of the wrong terminology > for the two tweaking knobs on your display: "brightness" > and "contrast". As said before, "brightness" relates to black level > (and as such it will have a direct influence on the contrast of the > picture). "Contrast" is brightning or darkening your white point > hence it is having an influence on the overall brightness of the > picture which shows the non sense in the choice of terminology... Contrast controls the linear component of the slope of the response curve of your display device it is not specifically a white point control. However, if you specify the black point (the start point of the response curve) using the brightness control then adjusting the slope with the contrast control must adjust the whitepoint within the limits of the device but it is not specificaly a whitepoint control. > > > > I don't believe that an observer is capable of making absolute > > luminance judgements. > > Of course not, since luminance judgement is subjective and varies > from one viewer to the other and with ambiant light. Which is why I > don't quite see the use of being able to set your black and white > point luminance value in Candela unit in the Spyder Pro software > version. How do these candela setting relates to the viewer assesment > of display luminance? > Yes but again, it is not the contrast that has to be adjusted for > comfort, it is the pedestal and the white point luminance > First you say '"Contrast" is brightning or darkening your white point' and then you say, 'Yes but again, it is not the contrast that has to be adjusted for comfort, it is the pedestal and the white point luminance'. Don't you think you are contradicting yourself there?
2006-04-26 by esimanor
--- In colorvision_group@yahoogroups.com, "Brian Smith" <zen1@...> wrote: > > Yes but again, it is not the contrast that has to be adjusted for > > comfort, it is the pedestal and the white point luminance > > > > First you say '"Contrast" is brightning or darkening your white point' > and then you say, 'Yes but again, it is not the contrast that has to > be adjusted for comfort, it is the pedestal and the white point > luminance'. > > Don't you think you are contradicting yourself there? No. The confusion comes from the wrong use of terminology when it comes to display tweaking knobs, as I tried to point out. When I refer to "contrast", I mean the knob called contrast on the display. when i refer to contrast without the ", I refer to the contrast of a picture, which is the real thing. I still maintain that when a display refers to "contrast" as a mean of adjusting your viewing device, it really means white point luminance level (rather brightness but certainly not contrast). at least that's what it was for a CRT. As pointed out earlier, i am not quite sure on LCD's. Of course, when you tweak your white point luminance with respect to your black level, it will have a marginal effect on the overall contrast of the picture since you will expand or reduce the span of your grey scale. But this is not like applying a gamma or an s curve....
2006-04-26 by Tom
--- In colorvision_group@yahoogroups.com, "esimanor" <esimanor@...> wrote: > Yes but how does one know how to relate between a setting in Candela > and the actual luminance level it will yield to the eye of the viewer? > Plus how do you take into account the level of ambiant light if what > you want is to achieve is respectively a given black and white point > luminance? > Thats a very good question. The answer is you need to use a color appearance model. These models predict observed luminance and hue based on multiple environmental factors. One of the current reasonably accurate color appearance models is given the name CIECAM02. First lets define two terms. These terms are "Brightness" and "Lightness". As seen in "Color Appearance Models" by Mark Fairchild these are defined as follows: ------------------------------------------- Brightness Attribute of a visual sensation according to which an area appears to emit more or less light. Lightness The brightness of an area judged relative to the brightness of a similarly illuminated area that appears to be white or highly transmitting. Note Only related colors exhibit lightness. The definitions of brightness and lightness are straightforward and rather intuitive. The important distinction is that brightness refers to the absolute level of the perception while lightness can be thought of as relative brightness normalized for changes in the illumination and viewing conditions. --------------------------------------------- One nasty twist of color vision is that using pure candela of a color is insufficient to determine the relative lightness of two samples given the same viewing conditions. When you are asking about luminance level ... do you mean lightness or brightness? Tom
2006-04-26 by Brian Smith
--- In colorvision_group@yahoogroups.com, "Tom" <ttrostel@...> wrote: > When you are asking about luminance level ... do you mean lightness >or brightness? I get the impression esimanor may actually mean luminance as measured in cd/sq m which is not a subjective thing.
2006-04-26 by esimanor
--- In colorvision_group@yahoogroups.com, "Tom" <ttrostel@...> wrote: > > One nasty twist of color vision is that using pure candela of a color > is insufficient to determine the relative lightness of two samples > given the same viewing conditions. > > When you are asking about luminance level ... do you mean lightness or > brightness? > > Tom This might be getting a touch too delicate for me. My concern is that i would like to think that me and my clients are seeing roughly "the same thing" when they look at my files... I think that I can instinctively grasp the concept of color vision and lightness versus brightness but how does this come into play when using a calibration gear with a software only allowing you to set your own black and white point in candela unit? Plus again, how does all this relate to your display adjustment knobs?
2006-04-27 by CDTobie@aol.com
2006-04-27 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > Here's the scoop. If you run an LCD at a relatively high candela value for > White Luminance, in a relatively light room, it will look (relatively speaking) > the same as a much dimmer CRT, with much dimmer ambient light (and a warmer > white balance as well, due to another variable in the eye). The Ambient Light > functions measure your room lighting, and define WhitePoint and White Luminance > target values that will make for this relative match, and the hardware > controls are used to reach these defined monitor target values. Is that clear enough? Well, not quite I am afraid... Ambiant light is less of a problem for me since I am in control of my work environment and my clients claim that they are too. But what do you call hardware controls? are these "brightness" and "contrast" on your display? in which case we are back to square one: what are the corellations and what is the purpoe of being able to fix your black and white point in candela units through software? have you checked the software update issue with customer support ?
2006-04-27 by CDTobie@aol.com
In a message dated 4/27/06 2:37:21 AM, esimanor@... writes: > Well, not quite I am afraid... > Ambiant light is less of a problem for me since I am in control of my > work environment and my clients claim that they are too. > Yes, but I often find this claim backed up, these days, with a very dark room with a high luminance LCD in it, creating glare, and inappropriate viewing conditions, or conversely, someone using a CRT under what THEY consider dim light, meaning not full US office lighting, but still way above what a CRT can be used for color work under... > But what do you call hardware controls? are these "brightness" > and "contrast" on your display? > Correct... > in which case we are back to square > one: what are the corellations and what is the purpoe of being able > to fix your black and white point in candela units through software? > Correlations to what, through what? The black luminance is monitor black, unless you choose to compromise that to the weakest black of a group of monitors, for exact side to side matching, and the whitepoint and white luminance are from the ambient target, and these candela values are reached by manipulating the hardware controls (front panel controls on most monitors). But I believe I've already said that, so I suspect there is a discontinuity between what I'm saying and what you're asking. C. David Tobie Product Technology Manager ColorVision Business Unit Datacolor Inc. CDTobie@... www.colorvision.com
2006-04-27 by Tom
--- In colorvision_group@yahoogroups.com, "Brian Smith" <zen1@...> wrote: > > --- In colorvision_group@yahoogroups.com, "Tom" <ttrostel@> wrote: > > > When you are asking about luminance level ... do you mean lightness > >or brightness? > > I get the impression esimanor may actually mean luminance as measured > in cd/sq m which is not a subjective thing. > Though he mentioned "to the eye of the observer" which depends directly on the observation conditions.
2006-04-27 by CDTobie@aol.com
2006-04-27 by Tom
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > Yes, Tom is an enthusiastic theorist, so what he's saying is both interesting > and true, but probably not applicable on a practical level... > Bad habbit. Its disturbing when only the "how" of a process has been explained to me. Knowing "why" always completes the picture and makes it much easier for me to do something .... like color management! Most of the color management stuff on the web gets close to explaining but stops short and doesn't have enough examples. This link was very nice however and cleared up a lot of my questions early on. http://www.cambridgeincolour.com/tutorials.htm If everyone would help maybe we collectively could make a better page explaining color management and the issues related to it. Would that be something everyone would like?
2006-04-27 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > Correlations to what, through what? I ment correlation between the tweaking of the knobs (which are usually accounted for in %) and the value of the white target in candela unit which you are trying to reach. >The black luminance is monitor black, > unless you choose to compromise that to the weakest black of a group of > monitors, for exact side to side matching, and the whitepoint and white luminance are > from the ambient target, and these candela values are reached by manipulating > the hardware controls (front panel controls on most monitors). OK, but how do you reach a specific candela value while tweaking your knobs? Does CV spyder give you a measurement of black and white point as you tweak or do you need an extra piece of gear specificaly aimed at measuring a display luminance in candela which you would stick in front of your screen while having a white chart and then tweak which ever knob until you get to the right setting? How would you then take ambiant light into account?
2006-04-27 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > Upgrade options and pricing from Spyder2express, the new kid on the block, have not > been announced yet, and could conceivably effect the Spyder2 to Spyder2PRO > upgrade pricing, when they come out... Spyder2Express is the one I just ordered. Any idea of when it will be possible to get hold of the software update? Is that going to be a site download?
2006-04-27 by CDTobie@aol.com
2006-04-27 by CDTobie@aol.com
2006-04-27 by esimanor
--- In colorvision_group@yahoogroups.com, CDTobie@... wrote: > Are you referring to a incremental update, or to a paid upgrade to Spyder2 or > Spyder2PRO? If its the latter, then the details should be announced next > week. If its the former, the latest version of express is already available on our > European site <www.colorvision.ch> and will be on our US site after the > current site upgrade is completed. Thanks. I will first want to upgrade to latest express version but later on i might well upgrade to 2suite or 2pro (depending on pricing)