Colour managment

[JRR]

I assume that MicroSoft's new colour control, available

here will not help us make PTE a colour managed software.

Is there a way that Igor can make it happen ?

Some people usually work in Adobe RGB and for best viewing results change the files used in their shows to sRGB.

[Igor]

The good idea, but the most difficult technical problem - how to mix two different images with differect color profiles in one limited sRGB screen in slide-show? Teoretically it's possible, but in this case we will need to mix images in back buffer with 16-bit per channel (48-bit). Only modern video card supports it. And officially Microsoft doesn't support this feature in DirectX.

However personally I think that there is no serious benefits to use color management in slide-show. The difference is small (after convertation in Photoshop from Adobe RGB to sRGB) and especially not noticeable in compressed JPEG images with 200-500 KB of file size.

[JRR]

Thanks for your reply Igor

Always there with knowledgable answers for us

[JohnB]

The good idea, but the most difficult technical problem - how to mix two different images with differect color profiles in one limited sRGB screen in slide-show? Teoretically it's possible, but in this case we will need to mix images in back buffer with 16-bit per channel (48-bit). Only modern video card supports it. And officially Microsoft doesn't support this feature in DirectX.

However personally I think that there is no serious benefits to use color management in slide-show. The difference is small (after convertation in Photoshop from Adobe RGB to sRGB) and especially not noticeable in compressed JPEG images with 200-500 KB of file size.

[JohnB]

I'm very fussy about correct colour management and always profile the projector using a Gretag Macbeth Beamer before every show. I've found that people can see the difference between sRGB and Adobe RGB (1998) on a projected image with a properly profiled projector. I'm very careful to ensure that all the slides have Adobe RGB (1998) profiles and that, as far as possible, they are saved using Photoshop JPG level 12. Although pic2exe doesn't explicitly say it handles colour managed images and projectors, it seems to do a very good job.

In my last show, I was projecting onto a screen 300 cm wide, and the audience of highly critical photographers were amazed at the quality of the images.

By the way, Windows colour management doesn't work too well with greyscale images; fortunately it's easy to convert them to RGB at the last moment before saving.

Another by the way: pic2exe behaves badly with CMYK images; the image sequence stops at the image before the CMYK one, but the music goes merrily on. Once again, a last minute conversion avoids the problem.

[sjhein]

John,

I'm very fussy about correct colour management and always profile the projector using a Gretag Macbeth Beamer before every show. I've found that people can see the difference between sRGB and Adobe RGB (1998) on a projected image with a properly profiled projector. I'm very careful to ensure that all the slides have Adobe RGB (1998) profiles and that, as far as possible, they are saved using Photoshop JPG level 12. Although pic2exe doesn't explicitly say it handles colour managed images and projectors, it seems to do a very good job.

In my last show, I was projecting onto a screen 300 cm wide, and the audience of highly critical photographers were amazed at the quality of the images.

I'm curious how you apply the profile created by the beamer to the slide show since PicturesToExe isn't color managed? Do you convert each of the image files to that profile?

I currently use the Eye One for screen and print calibration, but have been contemplating getting the Beamer accessory to calibrate my digital projector. However, the workflow I would use isn't clear to me yet.

Thanks,

-Scott

www.heinphoto.com

[Ken Cox]

Scott

do you mean

http://www.eye4u.com/home/

ken

[sjhein]

Ken,

do you mean

http://www.eye4u.com/home/

No, I was referring to the Gretag Macbeth "Eye One" color calibration system, which includes both a hardware calibration instrument and software to produce ICC profiles for both your display and printer. They also sell an attachment called a "Beamer" that allows you to use the same calibrator to create profiles for digital projectors:

http://www.i1color.com/

Best regards,

-Scott

[Ken Cox]

Sott

i still use my McBeth colour chart when things do not look right to calibrate my scanner to

but it is all in the eye of the user

one has to have a known value in a scene to work from

and if the end user's monitor is off all your work is in vain

ken

[JohnB]

Sott

i still use my McBeth colour chart when things do not look right to calibrate my scanner to

but it is all in the eye of the user

one has to have a known value in a scene to work from

and if the end user's monitor is off all your work is in vain

ken

The human eye/brain combination can easily be misled over colours; see any book on colour vision. In addition, about 10% of males have some form of colour vision deficiency (I do). Therefore, it's safer to rely on hardware calibration if you want to be sure of the end result. The Eye One Beamer creates a profile which sits in your computer between the colour managed images and the projector in exactly the same way as does the monitor profile.

I said before that pic2exe is not explicitly colour managed -- that's true, but it seems to work very well provided all images have the same colour space (Adobe RGB 1998) and the projector has been profiled correctly. Of course, if you're sending a file to someone else and have no control over how they've profiled their projector/monitor, you're at their mercy and will probably get the horrible 9300K, over-saturated, high contrast images I see far too often!

Join those of us promoting proper colour management!