Colour differences

[abra100pro 53]

See movie: Same shape - two different colour values.

 

[thomaso 817]

Where is the bug? – Your video shows a swatch named "0975d0" with its values "066DB6" / "88c 51m 0y 0k".

Note:
• A swatch name reflects its values only for its first auto-named version.
• The color values depend on the selected mode during creation. (e.g. cmyk, rgb, hex...)
• A color mode change is influenced by the document's color space + the profile.

[abra100pro 53]

I made swatches for this customer and never changed the colour. My docs all have CMYK/8 and I export them to either Coated or Uncoated FOGRA profiles.

[walt.farrell 4,046]

26 minutes ago, abra100pro said:

I made swatches for this customer

But how did you make that swatch, and how did it get its name. You haven't shown us far enough back.

[abra100pro 53]

I made it by entering the hex value into the hex-field and adding it to my swatches. I use theses swatches ever since and due to a colour conflict with the printer I counter checked to find the value being different. I dunno when It happened - I just know that I did not change the swatch.

[walt.farrell 4,046]

Thanks. In that case, I have no idea what's happening.

[Lagarto 576]

It is not clear from the video what has caused this problem, but it seems that your 0975d0 swatch might have actually been created in CMYK mode and just renamed using the hex notation. When you assign on the video the 0975d0 swatch to the object and then double click the fill color well on the Color panel, it can be seen that you have CMYK sliders active and the CMYK values are percentages. At least on Windows this is an indication that the color definition of the object has been given and saved as a CMYK value. If an object with an RGB definition is selected, the CMYK sliders show 8-bit values (0..255).

In the example below Coated Fogra 39 is used as the CMYK color profile (and sRGB as an underlying RGB profile). First an RGB swatch is created using hex notation #0975d0 which will get a CMYK conversion value of C85 M53 Y0 K0 in this profile context. Then a CMYK swatch is created using the C85 M53 Y0 K0 definition which will get an RGB conversion value of #256db5 in this profile context. The other of the blue rectanbles has the RGB version swatch assigned, and the other the CMYK version.

When the fill well of the Color panel is double clicked, the color mode of the swatch definition is reflected in the CMYK slider values: they are percentages when showing color values for a CMYK based swatch, and 8-bit values when showing color values for an RGB based swatch.

I am not aware of a situation which could cause an RGB based color definition in an application palette to convert to CMYK, but I have very little experience on application palettes. Is this a palette that you have used with multiple publications? Can you check whether its saved color definition for  0975d0 is really CMYK based or RGB based (or if this could be just a document-specific problem)?

Anyway, when I tested these definitions with a variety of different color profiles, both swatch definitions correctly retained their original definining color values (but were naturally converted differently to equivalent CMYK and RGB values depending on the profile). 

 

[Lagarto 576]

Here is an example of how PMS 2935 C (for coated stock) and PMS 2935 U (for uncoated) are translated to CMYK when using different apps:

pms2935_fogra27.pdf

pms2935_fogra29.pdf

When using PSO Coated v3 and PSO Uncoated V3 (Fogra 52), all these values would again be a bit different. And none of these values would take into consideration exact properties of a specific paper. You simply cannot give "correct", generic CMYK values. If color accuracy is important and you have a specific reference (like a PMS tone), you should use spot inks. 

[abra100pro 53]

Thanks Lagarto - the Pantone has nothing to do with it - I just switched shortly to it and then back to show that I really have selected the right swatch colour. But your answer above is interesting - I have to dive into this a bit more... I usually start with UncoatedFOGRA CMYK. I understand that the CMYK (and all other model's) colours is interpreted by not only the HEX code but other things like Profiles. I'm still confused about when this happened. I use this swatches in AD and APub in different documents.