Datacolor User to User Support Group.

With all the discussion on making the nose cones something other than
black I went to my garage, found a can of latex white paint and a
small brush.

My white nose cone does make reading targets very easy! Cost, too
small to calculate.

This modification suggests something that has concerned me, but which  
I have not carefully tested:

How sensitive is the reader to ambient light falling on the target?  
The instructions say nothing, one way or the other.

Just to be safe, I have shielded the target from direct lighting (eg  
my gooseneck work-desk lamp) when taking readings. Reasonable levels  
of direct lighting did not seem to make a difference when I looked at  
some of the numbers, but I have not had time to test all of the  
target squares for possible variation.

Myron

On Mar 13, 2006, at 9:43 PM, davedoughman wrote:

> With all the discussion on making the nose cones something other than
> black I went to my garage, found a can of latex white paint and a
> small brush.
>
> My white nose cone does make reading targets very easy! Cost, too
> small to calculate.
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>

--- In colorvision_group@yahoogroups.com, MGochnauer <goch@...> wrote:

> How sensitive is the reader to ambient light falling on the target?  
> The instructions say nothing, one way or the other.

Here's are some simple tests.  Lift your 1005 off the paper and point
it tword the middle of your room.  Take a reading.  Unless you have a
brightly lit room it almost always reads black or very close to it (at
least mine does).  Second take a reading and then deliberately try to
shine your light along the side of the paper under the nose.  Now no
cheating and lifting it off the paper!  That would cause the
illumination from the LEDs to decrease and isn't realistic ... though
the light show is kind of cool.  Mine doesn't change.  

Consider that the shroud on the colorimeter does a pretty good job of
shading the paper, that the LEDs are fairly bright, and any ambient
illumination on the target is at approximately 90 degrees from the
surface of the paper.  

You could probably calculate the contribution due to ambient light but
odds are its below the noise level.

The ColorVision folks could of course give you a much more technical
answer ;-)

I tested for this during the initial beta. Unless your light source is VERY BRIGHT and VERY CLOSE to the target AND the nose cone is NOT FLAT on the target there is no effect. Even then the effect was minimal and I doubt it would have a significant effect on the profile.

Regards, Walt

>-----Original Message-----
>From: MGochnauer [mailto:goch@...]
>Sent: Monday, March 13, 2006 10:41 PM
>To: colorvision_group@yahoogroups.com
>Subject: Re: [colorvision_group] White Nose Cones
>
>This modification suggests something that has concerned me, but which  
>I have not carefully tested:
>
>How sensitive is the reader to ambient light falling on the target?  
>The instructions say nothing, one way or the other.
>
>Just to be safe, I have shielded the target from direct lighting (eg  
>my gooseneck work-desk lamp) when taking readings. Reasonable levels  
>of direct lighting did not seem to make a difference when I looked at  
>some of the numbers, but I have not had time to test all of the  
>target squares for possible variation.
>
>Myron
>
>
>On Mar 13, 2006, at 9:43 PM, davedoughman wrote:
>
>> With all the discussion on making the nose cones something other than
>> black I went to my garage, found a can of latex white paint and a
>> small brush.
>>
>> My white nose cone does make reading targets very easy! Cost, too
>> small to calculate.
>>
>>
>>
>>
>>
>>
>> Yahoo! Groups Links
>>
>>
>>
>>
>>
>>
>
>
>
> 
>Yahoo! Groups Links
>
>
>
> 
>
>
>

MGochnauer  wrote:
> How sensitive is the reader to ambient light falling on the target?  

My observation with reading targets is the cone seals the ambient light to zero.

The LCDs are extremly bright and when a patch is read I see no light coming out from the 
cone....so the seal is excellent.

John

While we are on the subject, I was playing with my spectro just taking 
random measurements of materials, and noticed that the screen patch is 
noticeably darker than the material. .... like plastic, fabric...ect

Randy Laskody

Tom wrote:

>--- In colorvision_group@yahoogroups.com, MGochnauer <goch@...> wrote:
>
>  
>
>>How sensitive is the reader to ambient light falling on the target?  
>>The instructions say nothing, one way or the other.
>>    
>>
>
>Here's are some simple tests.  Lift your 1005 off the paper and point
>it tword the middle of your room.  Take a reading.  Unless you have a
>brightly lit room it almost always reads black or very close to it (at
>least mine does).  Second take a reading and then deliberately try to
>shine your light along the side of the paper under the nose.  Now no
>cheating and lifting it off the paper!  That would cause the
>illumination from the LEDs to decrease and isn't realistic ... though
>the light show is kind of cool.  Mine doesn't change.  
>
>Consider that the shroud on the colorimeter does a pretty good job of
>shading the paper, that the LEDs are fairly bright, and any ambient
>illumination on the target is at approximately 90 degrees from the
>surface of the paper.  
>
>You could probably calculate the contribution due to ambient light but
>odds are its below the noise level.
>
>The ColorVision folks could of course give you a much more technical
>answer ;-)
>
>
>
>
>
>
> 
>Yahoo! Groups Links
>
>
>
> 
>
>
>
>
>
>  
>

--- In colorvision_group@yahoogroups.com, randy <rlphoto@...> wrote:
>
> While we are on the subject, I was playing with my spectro just taking 
> random measurements of materials, and noticed that the screen patch is 
> noticeably darker than the material. .... like plastic, fabric...ect
> 
> Randy Laskody
> 

Yeah, luminance is a tricky one.  An example is the difference between
my Trinitron CRT and my LCD monitors.  Both are calibrated (D65,2.2)
but the LCD is a *lot* brighter.  Of course if you turn your viewing
lights down then at some point they will seem to match :-)

Thanks.  Your procedure and conclusions make perfectly good sense...  
but when I am trying out a completely new system that I must learn  
from the bottom up, I like to minimize the variables.  And in the  
beginning I'm not even sure what the variable *are*, so I don't trust  
my judgment!

Myron

On Mar 14, 2006, at 9:56 AM, Tom wrote:

> --- In colorvision_group@yahoogroups.com, MGochnauer <goch@...> wrote:
>
>> How sensitive is the reader to ambient light falling on the target?
>> The instructions say nothing, one way or the other.
>
> Here's are some simple tests.  Lift your 1005 off the paper and point
> it tword the middle of your room.  Take a reading.  Unless you have a
> brightly lit room it almost always reads black or very close to it (at
> least mine does).  Second take a reading and then deliberately try to
> shine your light along the side of the paper under the nose.  Now no
> cheating and lifting it off the paper!  That would cause the
> illumination from the LEDs to decrease and isn't realistic ... though
> the light show is kind of cool.  Mine doesn't change.
>
> Consider that the shroud on the colorimeter does a pretty good job of
> shading the paper, that the LEDs are fairly bright, and any ambient
> illumination on the target is at approximately 90 degrees from the
> surface of the paper.
>
> You could probably calculate the contribution due to ambient light but
> odds are its below the noise level.
>
> The ColorVision folks could of course give you a much more technical
> answer ;-)
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>

--- In colorvision_group@yahoogroups.com, MGochnauer <goch@...> wrote:
>
> Thanks.  Your procedure and conclusions make perfectly good sense...  
> but when I am trying out a completely new system that I must learn  
> from the bottom up, I like to minimize the variables.  And in the  
> beginning I'm not even sure what the variable *are*, so I don't trust  
> my judgment!
> 
> Myron

Heh ... its okay.  We all did the same thing.  The unit is very solid!