Preflight PDF if there are RGB-images without any ICC-profile

[the_brain]

Roel,

FYI

In PitStop 08 you can create an Action List that will trigger this as well...

Select all
Select images
Select by color space (DeviceRGB)
AND
log selection

cheers,
Bert

[rich apollo]

A case of inconsistent nomenclature. Why does PDF (or Acrobat) have DeviceRGB or CalibratedCMYK instead of tagged and untagged?

[leonardr]

Originally Posted by rich apollo

A case of inconsistent nomenclature. Why does PDF (or Acrobat) have DeviceRGB or CalibratedCMYK instead of tagged and untagged?

PDF supports 11 different ways to represent color that have evolved over the 15+ years that the standard has been in existence PLUS the 10+ years that proceeded it with Postscript. In other words, Color has come a long way .

Just to clarify, the colorspaces are:
DeviceGray, DeviceRGB and DeviceCMYK - these are all "untagged" AND device dependent
CalGray, CalRGB and Lab - these are "untagged' _BUT_ device independent
ICCBased - this is tagged AND device independent

in addition, there are the various special colorspaces
Indexed
Separation (aka Spot colors)
DeviceN

and then
Pattern - which is treated as a colorspace in PDF

[Al Ferrari]

Hi Leonard,

What is the difference between Separation (aka Spot colors) and DeviceN color spaces?

Thanks,

Al

[roel78]

The preflight I have created is not perfect. The preflight contains a check on DeviceRGB images that will give a warning. But the preflight also contains a fix that will convertion all RGB images to destination CMYK.

When I use this combination in a preflight, Acrobat will do the conversion, but gives no warning when a DeviceRGB is used. Acrobat will use the assigned profile that is set in the fix.

The reason I want this warning AND fix: I want to contact the author when he used an untagged RGB and I want to give him an example when I assign the Adobe98-profile. (In most cases the author can't find out what was the original profile.)

[Lukas Engqvist]

I would reason that untagged is sRGB for the reason that the only occurences of untagged RGB is www, and that is sRGB, but that is my opinion. Also windows, HP and consumer devices assume sRGB.

[rich apollo]

Leonard,
I'm confused.

DeviceRGB and CalRGB are both untagged. One is device dependent and one is device independent. How is that distinction made without an ICC profile? As I understand it: device dependent RGB is in an RGB output-device colorspace - device independent RGB would be in a RGB working-space colorspace like sRGB.

CMYK is always device dependent, so I understand that.

I didn't realize that grayscale could be device independent. Again, without ICC profiles, how is the distinction made between DeviceGray and CalGray?

Being ICCbased shouldn't mean that the color is device dependent.

[romeljmendez]

Anyone,

I'm tying to convert cmyk files from the out source file to our cmyk profile. But I notice when I converted it to our working space or embeded it, the single black channels became 4 colors or converted into rich black.

How can I convert it without affecting the purity of the black channels?

[romeljmendez]

icc profile

[mattbeals]

You can't just use an ICC profile. You need a device link profile for this. Callas pdfToolbox plug-in, stand alone, Server, CLI and SDK can properly apply the device link profile. What space are you converting from and what is the destination space?

Device link profiles allow you map CMYK from one space into another while preserving the black plate. A standard ICC conversion from CMYK to CMYK will not preserve the black plate.

It's not hard to get a good device link profile. Send me the PDF and let's see what's going on. Or in the least send me the ICC profiles.