CMYK to RGB conversion

[Ross Penn]

Hi folks,

I used PowerPoint 2003 to create a presentation containing some JPEG
images in CMYK format. I'm getting complaints that the images won't
display in PowerPoint 2000, so I need to convert them to RGB.
So I've opened the original CMYK images in Photoshop, converted them to
RGB and saved them. The weird thing is, the RGB versions of the images
look different to the original CMYK images in PowerPoint; the colours
are considerably lighter in the RGB version.
I guess the way PowerPoint converts CMYK to RGB (for display) is
different to the way Photoshop does it. Does anyone have any idea how
PowerPoint does this conversion?

Thanks in advance,

Ross Penn

 

[Troy @ TLC Creative]

RGB and CMYK use different color space, so when an image is converted it is
changed to that formats color space. In genereal CMYK has a much smaller
color range, as it is for print. When you insert a CMYK image into PPT it is
not being converted, but you are seeing a CMYK image. The problem is early
versions of PPT do not support CMYK images (hence your user problems). When
converting in Photoshop I recomend changing to RGB (IMAGE >> MODE >> RGB),
then adjust with the curves tool (IMAGE >> ADJUSTMENTS >> CURVES) to
"restore" the image as close as possible to the original color space.

 

[Ross Penn]

Steve,

Thanks for the hint - that looks like a good place to start figuring
out what's going on.

Ross