[ka.johansson]

I'm having some difficulties with OmniGraffle exporting the wrong colors when I'm exporting a canvas as png.

My problem: If I create an empty canvas and set the canvas fill color to solid red (ff0000), export it as png, open the png in pixel editing software of my choice (Pixelmator) and the supposedly solid red shows up as ff1b18. Further investigation using DigitalColor Meter reveals that the "solid red" is actually ff1b18 in the OmniGraffle editing area as well! What's more disturbing is that even the preview color in the color picker window is ff1b18 although the sliders are at the 255,0,0 positions!

Perhaps this is not a OmniGraffle problem but rather some sort of generic system color profile problem. Still, I don't know what to do. Please help me! :)

Thanks!

// Karl


Update: I just tried calibrating my display in System Preferences > Displays > Colors > Calibrate... and this did indeed change the exported colors, and the DigitalColor Meter reading inside of OmniGraffle as well. When trying my best to calibrate the display, "solid red" ends up as ff1a17 and when I on the other hand try to center all calibration sliders (as uncalibrated as possible?) I end up with ff1412. Still far away from actual solid red (ff0000).

Please advise!

// Karl

[whpalmer4]

Try the following:

Open Textedit, type cmd-T to bring up the font selector, click on the color selector and set the color choice to FF0000. Now bring up the DigitalColor Meter and read that value. My bet is that you end up with something other than FF0000.

DCM returns the numeric value being sent to the display hardware and software, not the value that is actually produced. When you calibrate the display, you are building a dataset that describes the transformation between the colors you ask for and the colors you get. If you change the color calibration, DCM returns different numbers for the same graphic. The idea behind calibration is that your screen produces the same color for a given R,G,B combination as another device does, though in nearly every case, to actually get that color (R,G,B) on the screen you'll have to send (R+x, G+y, B+z) to the hardware. I notice that if I set my color profile to Generic RGB, DCM reports #4F4F80 when I've set the color to #505080, but the colors on the screen are way off! I do have an x-rite eyeOne Match color calibration gadget which I use every other week, and it is possible to see the change in the color rendition (and brightness) of the display with age.

If you make a file with a graphic in it with fill of some known color (say FF0000), then save the file as a flat file, not compressed (for ease of examination), you'll see that OmniGraffle specifies the color as 1,0,0 even though DCM is returning some number that may be substantially different from FF0000. If you use a properly calibrated display and send the file to a colleague who also uses a properly calibrated display, and the color matching settings are correct, the image on the two screens should be very similar, and that red should look red, no matter what DCM reports. Without calibrated output devices, save yourself a lot of headache and only do black and white diagrams :-)