Message
Re: [colorvision_group] Re: PFP Suite with Fuji Frontier F340
2006-04-26 by CDTobie@aol.com
In a message dated 4/26/06 10:55:12 AM, hanson102@... writes:
1. Monitor Profiling:
The purpose of using the Spyder is to be able to calibrate a monitor -
being able to adjust the monitor to its white point (eliminating color
casts),
Eliminates global color variations caused by differing definitions of white... one form of color cast.
which is why the goal of adjustments is to equalize R, G and
B.
Thats one goal of it...
The profile created through using the Spyder is the Monitor Profile.
Correct... which is assigned to the monitor at the OS level, and used automatically by color managed apps like Photoshop. The calibration for the Videocard is a tag within this profile that is supposed to be applied at startup. If this does not happen, or someother startup item overwrites it later in the startup process, than casts may occur.
Should I be calibrating 5 CRT Monitors together to make all 5 Monitors
render the same brightness and white point, I should have a standard
setting that I follow. Such as:
Display Type: CRT
Gamma: 2.2
White Point: 6500K
Plus, if they are side by side, a common chose of black and white luminace for all five (if they are not in the same room, this is not critical).
Otherwise, if I use different settings for different monitors, then I
won't be able to achieve the standard "look" - brightness and white point.
Brightness is very relative, and color balance matching requires appropriate ambient lighting, as your eye perceives color differently at different luminance levels.
At the end of the process, each of the 5 Monitors will have its own
unique Monitor Profile.
And video corrections...
I understand that Monitor Profiles created is
intended for the Monitor it was calibrated from. Should I assign
Monitor Profile of Monitor A to B, there is a high probability that
Monitor A and B won't render the same look because no two Monitors
functions the same due to wear and tear and other factors.
Right...
Using the Spyder doesn't guarantee that all Monitors can be calibrated
because some can be so worn out being unable to achieve the standard
needed.
Correct...
2. Monitor Profiling in our Frontier Lab:
I believe that I don't have a problem with how our monitor looks. I
don't see any color casts that would make a photograph look reddish or
yellowish or to any effect.
I've had users swear their monitor was reddish, but when I darkened the room to the appropriate ambient level for CRTs (CRTs must be used virtually in the dark) and placed a proper light booth on the desk, and a proper gray card in the light box, the hue of gray on screen in Photoshop matched the gray in the light box perfectly. Without these other factors, simply looking at the screen and saying "its reddish" or "its neutral" means very little.
Simply put, if view a large white patch
on the screen, it literally looks white - not yellowish white, reddish
white, greenish white nor bluish white.
This is a function of the eye (or visual system) called white point adaption. In a dark room, with a projector, I can run a Photoshop gray ramp on the peach walls of my livingroom, and the gray ramp runs from black to white, no sign of peach, even though I know for a fact that the wall its being projected on is peach. So this tells you nothing about the color of the monitor.
I believe that my problem
lies more on the Profiling Process of the Frontier.
This may well be true, but its not guaranteed from your description, and your assumptions...
3. Printer Profiling:
The goal is to be able to present an image in the monitor the way it
will be rendered on print.
The indirect goal The direct goal is to be able to print a standard test image so that it looks like a reference copy of that test image, within the gamut limits of the device.
Since there are different factors that
affect color rendition on print, we should create Printer Profiles
according to combination of Printer Type, Ink and Paper.
If those are the items your printer uses. A frontier does not...
If for example, I have 2 paper types (Matte and Glossy) coming from 1
set of Machine+Ink (Frontier), then I should create 2 different profiles.
For different reasons than with an inkjet. Here it is that the chemistry may effect the two papers differently, or that the texture may make midtones less dark than on a gloss print. We can't make black blacker, but we can adjust the midtones with a profile.
- Frontier-Matte-042606.icc
- Frontier-Glossy-042606.icc
The Spectro is the tool to use to be able to measure color values
created by a printer.
Yes, for the purpose or characterizing that printer.
4. Color Profiles:
Image files contain a color profile. An image taken by a Digital
Camera with sRGB as its assigned profile, embeds sRGB profile into the
image file. Should we need to edit an image using a different
profile, we have to convert the embedded sRGB profile to the required
profile - ex. Frontier-Matte-042606.icc.
I wouldn't edit in an output space, expect for making an image device specific. Even then I'd generally proof to that output profile from my Photoshop workingspace, and edit that way. Conversion to an output profile should be the last step before printing.
If I view one image file (with sRGB profile) on 5 of my Monitors, it
should all look the same.
Correct...
If I assign 1 image file among the 5
separate Monitors&Computers, with a different profile
(Frontier-Matte-042606.icc), that image file will look different among
the 5 Monitors even if they are all calibrated correctly.
No, if you do this right, and either proof to the output profile, or convert to it, and tag that profile to the image file, then the result will still look the same on all five monitors, whether it looks the same is it did from sRGB is another issue.
It is also possible for an image not to have an embedded profile as
with the case of the Target Prints bundled with the Print Fix Pro.
This allows us to print the Target Prints without bias from any other
color profile. The printer will print the Target Prints as how it
interprets it.
This gets messy. If you assign AdobeRGB to the target, then tell Photoshop to print it "same as source" (older versions) or "no color management", then it will give the same result as printing it untagged. The frontier, if it has no profile conversion in its software, would give identical results to tagged and untagged images. In fact, if you assigned (not converted to) different profiles (sRGB, AdobeRGB) and saved those as tagged images, and sent them to the Frontier, that would tell you whether or not it reads tags. If the two files printed differently, it does (making color management more tricky) if they print the same, from the same image date, but assigned different profiles, then the device ignores profiles entirely (making it necessary to convert elsewhere in advance, but at least providing the consistancy needed for color managed work).
5. Converting Color Profiles:
If I am a photographer working on my image of which I intend to print
on Matte Paper on a Frontier Machine, I should have a calibrated
monitor and the Frontier-Matte-042606 Printer Profile from the printer
I will have print done.
Since images from Digital Cameras are assigned either sRGB or
AdobeRGB, my photographs will look different when I view it on
Photoshop against the printed photograph.
Not much different, as its a wide gamut device, with bright whites and dark blacks, so proofing won't change things much...
Should I want to view the image file as how it will be printed, I
should convert the image file with the Printer Profile -
Frontier-Matte-042606. This should be the initial step as well should
the image to be printed needs to be enhanced.
No, you should proof to the profile with custom proof setup, and convert to it just before printing... but thats getting picky...
6. Viewing Images on the Monitor Against Frontier Print:
After creating Frontier-Matte-042606, i use this profile to determine
how my image in the monitor will look when printed. This I believe is
the essence of what the Print Fix Pro is capable of doing.
It does two things: convert images for printing (the part most people use), and give you tools to preview an image, check the gamut limits, and bring out of gamut colors into gamut on your own terms, as well as adjust shadow detail and other device specific stuff. This is the part of printer profile use that is often neglected...
The steps
that I do is simply opening the image file that was captured by the
Digital Camera with sRGB Color Profile in Photoshop and then Convert
the color profile to Frontier-Matte-042606, save the file, then print
through the Fuji Frontier Interface.
That should work...
My problem is that the colors are off. It is not because of the
monitor as I believe my monitor is well calibrated. Image viewed on
the monitor is reddish. The skin tone is reddish.
When in the printer space, you mean...
If I convert the
color profile of the image back to sRGB or even AdobeRGB, it looks
more natural, closer to skin tone.
There should be virtually no color cast in this conversion or reconversion process. There is an error somewhere for this to be occuring...
Am I missing anything here? Do I have the correct understanding of
the whole process?
You have a very servicable understanding of color management...
Where do you think the problem is?
My guess is that something is wrong with the settings involved in building the profile. We need to go over them in detail, but we don't need to do it in a public forum. I'll need you to send me, privately, screenshots of all the settings and configurations in your frontier software, for starters.
C. David Tobie
Product Technology Manager
ColorVision Business Unit
Datacolor Inc.
CDTobie@...
www.colorvision.com