Some members had recently questioned the quality of the digital display during the nvps competitions.  The most common complaint was its being too bright and blowing highlights.   

Matthew Schmidt has spent considerable time in identifying the root cause of the supposed problems, and in determining solutions.   Thanks to Matthew for his efforts in resolving the problems.

 Below is a summary of the preliminary findings and some suggested guidance to improve your images for the digital competition at nvps.   Notice of errors and omissions along with additional suggestions or tips is solicited.   Additional resources also welcomed, as are suggestions for further tests and measurements.

Two main issues are involved:  color fidelity/gamut,  and  white/black points of the dynamic range.   

Good news:  The apparent problem with "blown" highlights was traced to the projector.   Apparently Artificial Intelligence is genuine stupidity.  The projector kept changing its settings, thinking it knew better than we did how we wanted it to work.   We now have a procedure to ensure that the projector is properly set , and stays that way, when we use it.  

Additionally the projection PC/display_card/LCD_projector  has been calibrated and profiled.   Using the current profile will help provide consistent image  presentation from meeting to meeting.   You really don't need to use it unless you are truly picky about your colors, but should do so anyway  in order to ensure that your images are within the dynamic range that can be displayed.   For now you need to ask for the profile  to be sent via email.  Maybe in the future it can be posted on the nvps website for downloading.

Just plain news:  The profiled  color difference is  minimal compared to the straight sRGB that the projector uses.   Full disclosure:  My wife claims that I am color blind (even though my eye doctor disputes this).   However, Some other members  who looked at our test images did see some subtle changes that I could not.  

Recent test images show that any good image in the usual aRGB, sRGB, or the profiled sRGB color spaces have minimal differences, although all are duller when compared to a good print of the same image.   All look natural when viewed separately.   If your colors are bad it is not the equipment.  And  it is still your responsibility to take advantage of what can be done within the projection medium  limitations  just as is done with your lenses, cameras, software, printer/ink/paper, etc.   

Bad news:  We have met the enemy and they is us.   Any apparent problems now  are for the members to fix for themselves.   Suggestions for doing this are below.    

Blown highlights are no longer the fault of the projection equipment.   
Competitors are responsible for ensuring that their brightest tones are not more than pure white when captured or photoshopped.   If you use perceptual or relative colorimetric when converting to the LCD profile the white point of the image should be mapped to the white point of the projected image.  

Testing shows that we can get about 5 stops of dynamic range, with an estimated dMax (measure of the blackness achievable) of about 1.5 to perhaps 1.8 or so.    Using a test strip with increasing density of  %Luminance shows that  a loss of shadow detail  will occur at a value of about 95%K as measured by photoshop info.    So if you have a low key image you will need to adjust it so that you do not lose detail.   If you do this to a normal color image, they will look like they were overexposed or being viewed through fog  if you adjust them the same amount as a low-key bnw (black and white,  or monochrome) style image requires.   You need to determine the optimum compromise between the various settings  for your image.  

The dynamic range fix can be done in a number of ways.   If you use Kpt
(Black Point) compensation on during the conversion, it will map the black points, and the dark tones will suffer minimal blocking.  But you may still need to use curves , or set the in/out points in levels , for the best projected image, especially if your monitor shows more of the steps on the test image than are seen when projected.  

If your image has more than 5 stops of dynamic range you will either lose shadow detail or blow the highlights unless you make appropriate adjustments to compress it.    

Converting the image color space to the projection profile using perceptual with Kpt on will map your colors and the dynamic range to that which can be projected by also mapping the black point of the image to that which can be projected.    Or, with your  monitor set to display a soft proof of the simulated projected test image,  lowering the curves on the dark end (pull upper right corner down half a box) to about 90-85% would open up the dark tones to display correctly.   The same thing could be done in levels by sliding the middle slider halfway  towards the dark end, or by typing  25-40 (10-15% of 255) in the left box at the bottom.  This is not recommended for normal color images, but only for low key bnws.   

Note that your PC monitor may well show more detail than the projected image.   Using an ISO IT8 or Kodak Q80 test image that shows the full range of neutral tones can be used to see how your monitor  matches up with  the projection equipment.   Be sure the sample you download actually runs from 0% to 100%K.  There are inaccurate copies of these images on the internet so check the one you get with photoshop info.    On the IT8 image's 22 step scale,  the last 3 dark tones will merge on the projected image, and the next two will be just distinguishable.  Note that most density strips are nonlinear.  Use the info tool to check the actual K values.   Your PC may well display all of the steps if you have the brightness cranked up.   An old monitor that is not so bright may show less detail than the projected image.    

We have not yet measured the brightest tone that can be actually displayed, nor the actual darkest one.   For prints, maximum brightness depends on the paper whiteness.   For projection, that value depends on the brightness of the lamp, and the reflectivity of the screen.    Likewise, the darkest tone that can be displayed depends on the darkness of the room.  With the vending machines and hallway lights always on, pure black will not be achievable.   However,  a natural looking image will result if you map your image black point to the profiles black point by checking the box marked use black point compensation.  


Whilst the extreme displayable  values still need to be measured,  clearly the brightness will  be greater than a perfect 0%K and darkness less than a perfect 100%K.   IE pure white is not ever fully achievable, nor is pure black.   And the projector cannot display the darkest tones distinctly in our room.  These light/dark points that are achievable limit the dynamic range of our projected images.  

A pure white as set in photoshop does look natural on screen, because the white point of the image was mapped to the white point of the projection capability for our tests;  however with the propensity of judges to yell "blown highlights!" it might be safer to nudge the brightest tone down a couple of percent.   Naahhhh.  They will still say it.

Any picture that looks good on a calibrated  monitor should look good when projected.   Slight improvements can be made by using the projection profile and/or levels/curves adjustments.   Spending more time on content and composition may be more beneficial to winning though.  

Bad news:  Most people don't use a calibrated monitor.   At a minimum you should use Adobe gamma to set the white point and contrast as well as the color temperature.  Gamma should normally be 2.2 and the color temperature 6500.      

There are several  other, some  free,  adjustment programs and test images on the net that can be used to ensure a more accurate dynamic range of a previewed image.    Downloading a color chart such as IT8 or Q80 or a Gretag-Macbeth can also be useful if you have the ability to  adjust your monitors colors.   It is highly recommended  that you also get the PDI (Photodisc) test image to use as a standard for all your color management.  It can also be downloaded from iprintfromhome.com.

After calibrating your monitor you may want to also use a profiling device such as Spyder, Monaco, Gretag-Macbeth,  or other similar ones  that will adjust the output table used to drive the monitor in order to improve color fidelity.  

Ease of use and accuracy will vary as does cost.   Always check reviews before buying anything as expensive as these devices  in order to make sure it really meets your needs.   Some of the more expensive ones can also profile your printer/paper/ink and your scanner.

Reminder:  Always save your original image  immediately upon capture.  Make a working master for use with  adjustments, and then a working copy from that master to actually diddle.    Then make a copy of your adjusted image before making further changes in order to make a final version for digital display.  Sharpening should always be done last.

We cannot provide an exhaustive description of all the suggestions below.   The reader is referred to their photoshop help function as well as a book on photoshop and/or color management for elaboration.  
Normankoren.com and other websites have tutorial material that could also be useful.   GIMP and other programs also have guide books available.  Maybe a future workshop could cover all these items in detail if the members wanted such a presentation.  It could be useful to see the printed versions of the sample images along with the projected ones and the soft proof/gamut checking  changes.   You can always ask questions before a meeting or during the break.  

In order to use the profile for the projection equipment you must first get the file.   Then you must put it in the correct folder on your PC.  

Photoshop help  lists where you should put the profilename.icm file for the projector depending on your OS version.  Or you can just do a search for *.icc and *.icm and see where your PC keeps those files.  

The nvps profile is named yyyymmdd.icm, indicating when it was created.   It will be updated periodically.   This file shows up as spyder2pro in drop-down lists.   

Once the file for the profile is in place then you are ready to use it.   The primary uses will be for conversion to the profiled color space, to do soft proofing, and to do a gamut test.

If you convert your image to the projection profile using perceptual (for normal images) or relative (for extreme color)  with Kpt on,  then you really do not need to do a gamut test.   What you see is what you will get when the image is projected (within the capability of your monitor,  and   it will be fairly indicative of the colors but not the dynamic range unless your monitor is (mis)calibrated to match the actual projected dynamic range).

Note that if you convert the image's  profile you may need to save it first,  close it, and reopen it to make sure that any subsequent soft proofing and gamut are displaying correctly.  This quirk was noted in PS7.  CS2/3 may be different.  Don't know, can't say about GIMP, Corel, etc.

The following are PS7 commands.  CS2/3 may differ.  GIMP, Corel, etc. should have similar capabilities.   

In order to use the gamut check , first go to
•    edit
•    preferences
•    transparency gamut
•    color preferences - set to white for now
•    opacity - start with 50% for now

This will make out of gamut colors turn to a light gray when you do a gamut check (see below for gamut check info).   The affected colors should be obvious as it is usually the darker tones that are out of range (white is in the middle of the CIE diagram and is not a problem) although some lighter extreme colors can also be out of gamut.

Before checking the gamut or proof colors you must select:
•    view
•    proof set up
•    custom
•    select:   sypder2pro / perceptual / use black point

warning:  if you omit this,  the tests below will work but be misleading
Relative colorimetric may be better if you have extreme colors.   Without the Kpt (black point) on the darks will block up sooner.

Once proofing  is set,  then you can check the gamut and  the simulated projected image:
•    toggle ctl-y to see the proof colors (simulated projected image)
•    toggle shft-ctl-y to see what is out of gamut BEFORE conversion of the image to the profiled space
or alternatively you can use view and then select proof or gamut.

Keyboard commands can be toggled more easily to see the differences faster.

The gamut test will show the colors that will change when the image  is converted to the projection profile.   Normally the image with the new profile colors is satisfactory and you do not even need to worry about gamut.  If not,  you will need to guess how to change the image before conversion to see if you can improve the colors and dynamic range EG change hue/saturation, brightness/contrast, curves/levels, etc..   Alternatively you can use other conversion parameters to see if they give a better result.   

If you have converted the image , saved it, closed it, and reopened it, then the above tests should show no difference when toggling ctl-y or shft-ctl-y as long as you again set up the custom profile to spyder2pro instead of the default which is now most likely SWOT 20% dot gain.  

If you assign the digital projection profile then it is temporary.   In order to permanently convert the profile of the image use the following:
•    image
•    mode
•    convert to profile
o    spyder2pro - pick from drop down list
o    ace
o    perceptual (can try relative if have extreme color)
o    use kpt on
then save, and close the image before further use.


To select the info tool to check actual color amounts or black point density first click on :
•    window
•    and turn on check mark for info
then
•    select the info tab
•    maximise it
•    click right pointing triangle near upper right corner
•    palette options:  select  RGB  &  grayscale

Where you position the arrow will read out the color and darkness at that point.  

To check the Kpt density and RGB color amounts select the info tool and then choose the RGB and K options.  It is easier to use with the arrow than the hand in order to identify the point being measured.  

It is recommended to first try to  change the image to the spyder2pro profile, save, close, and reload, then check the soft proofed image, before messing with the gamut tests.   If you are happy with that image you do not really care what was out of gamut before the conversion.   If you do choose to  make your own changes to the gamut, consult a book on color management for guidance.


You may also  want to  adjust some other "hidden" variables in Photoshop to simplify some related dialogue selections, or to remind you not to make a mistake in handling the color management functions:
•    edit
•    color settings
•    working = adobe rgb ( or wide gamut, kodak prophoto,etc.)    prophoto not recommended unless you use only 16bit processing.  
•    conversion
o    perceptual
o    kpt on