Hi Everybody,
It has appeared to me for a very long time that the CMYK colors chosen from the CMYK color docker do not display correctly in either DRAW or Photopaint.I have no idea why this is happening.
Here are five hues (tints, whatever) for equal value for magenta and yellow. Those values have nothing to do with the eyedropper tool. They are the entries in the CMYK color docker. The hue starts out as red. Then almost immediately shifts to orange. Then to orange-yellow. That does not happen if you vary the transparency of the (0, 100, 100, 0) layer. In that case, the hue remains constant as the lightness varies.
I have simply ducked this problem by using RGB. The hue remains constant in RGB as the values are changed proportionatately
Just out of curiosity, has anyone else noticed this behavior. Could it possibly be "normal".
Here's CMYK:Here's RGB:Phil
HI Phil
it is not your imagination it is the way cmyk works
As you know the cmyk color space is based on printing inks those inks are in fact transparent do you see anything transparent in your cmyk objects, no because they are displayed as though opaque on white the hue change is because 0 black is 100% white you are changing the colors m and y in relation to 100% white
this shows the difference between applying transparency and mixing percentages of colour both print the same but the display properties are different due to an alpha channel being used for transparency
The eyedropper sees both as the same value.
Ross Blair
The capture posted here shows the swatches from another post with the C0 M100 Y100 K0 again at 50 % transparency, at C0 M50 Y50 K0 and the transparency converted to a CMYK image.
The captures shows the image displaying the same as the C0 M50 Y50 K0 as it should the eyedropper reads the transparency the vector and the image the same.
Herein lies the rub, those who design by eye cannot rely on the eyedropper tool it's incorrect per the display, if they want the C0 M50 Y50 K0 look and they adjust the transparency to the eyedropper and then import or build other vectors to match they have problems.
Again, there is another rub, all RIPs are not created equal! The conversion of transparency is not controlled by the Adobe specification in their license. Prinergy, Apoge and Meta do a good job, later versions are all PDF RIPs supporting live transparency other PDF RIPs are not as robust. Postscript RIPs have much more serious variations.
I was called on a job for a sign company doing vehicle graphics a while back the client an energy company had a logo with multiple monotone shades and gradients and unpredictable variations of the logo was printing. The files were AI MAC created by their client, as it turns out the two designers they had working did the logo differently one used true vector shading and gradients the other used transparency. The logo with transparency was printing differently then the true vector version and differently on different devices. USE OF TRANSPARENCY NEEDS TO BE TESTED ON THE DEVICE before output behaviors can be predicted.