Placing PNG... the good and the bad

[Lukas Engqvist]

I was preparing for a colour management seminar and find my PNG screen dumps are no longer placable unless the file is sRGB (InDesign now gives error that the file is not a valid PNG if it has other profile than sRGB...*that is the good part)

The bad part is that if the InDesign file has other RGB than sRGB the PNG will not show the right colour…well we should be having sRGB as the (Untagged) RGB workingspace.

So far in agreement. But still alas the Adobe shipped General purpose settings have sRGB and the Prepress settings AdobeRGB.

That means I must recommend General Purpose settings as the better option for for prepress. (And Prepress is only good for Photographers, maybe they should be renamed... and why still the warning for unsynchronised settings and for RGB images in preflight, is what I'd like to know.)

[Colorblind]

Doesn't fix the png issue but one quick workaround would be to use .jpg as the screen capture file format. Your default monitor profile should then be embedded in the JPEG. The following script is an example:

set myscreencapture to ("screencapture" & ".jpg") as string
do shell script "screencapture -tjpg " & quoted form of myscreencapture

also found this on Mac Forums | Apple, iPod, iPhone Discussions (but haven't tried it) to make jpeg the default file format when performing a screen capture.

Open Terminal (Applications>Utilities>Terminal) and type in
"defaults write com.apple.screencapture type jpg" (without quotes)
then log out and back in for results to take place

[Lukas Engqvist]

I use SnapsProX so for screens it's not a problem, was just a curious thing. It started up as a customer that wanted small size masked photos with soft transparent shadows, the PNG 24 seemed a natural way to do it, only since the profile wasn't honoured the PNG don't respond to standard colour management in workflow... not realy a problem as long as one is aware of it.

[Stephen Marsh]

Lukas, I simply would keep the colour settings as they are not suggest using an internet display image format for a (mostly) print layout application - and use PSD/PDF image instead (both support colour profiles and transparency). Keep PNG for the WWW and perhaps MS Office.

Stephen Marsh

[rich apollo]

If you look at the spec, PNG is sRGB or not sRGB. That's the whole of PNG color management.

[leonardr]

If you look at the spec, PNG is sRGB or not sRGB. That's the whole of PNG color management.

Correct.

PNG supports the inclusion of an associated RGB (or Gray) profile. In that case, you can use any profile that you'd like. If you don't use a profile, then it's sRGB.

[Lukas Engqvist]

@leonardr + rich apollo.

The point is that a PNG can be created with other profile than RGB (either by a screen dump, Photoshop or a variety af other ways) Older versions of InDesign would allow placing the PNG but would ignore the profile if it is there or not. This meant a PNG would appear different in Photoshop or InDesign.
Today to be placed in InDesign a PNG must have sRGB as profie or no profile (which according to best practices means that the files colours should be sRGB since this is the only RGB that may exist with no ICC profile) So far I am just stating the playing ground.

The problem is that all untagged RGB is in InDesign Document RGB. This means that Document RGB must be sRGB in InDesign for PNG to display correct. My two objections are:
1) Adobe Prepress defaults make AdobeRGB the Document RGB and thus the profile for all untagged RGB images. This goes against ICC practice. Since all images with ICC profiles can use their embedded ICC profiles InDesign should give a warning if sRGB is not the profile for untagged RGB images!
That the "Prepress" colour setting has the wrong ICC for untagged RGB is alarming.

2) Since many want to work with AdobeRGB in Photoshop, which is fine they will have AdobeRGB as default RGB in photoshop. Many insecure users will freak out if bridge does not have synchronised profiles, this should not be a problem though. The warning system needs to change, or alternatively there should be 2 RGB profiles in the document settings, one for "working RGB" and one for "untagged RGB" (which should in all cases be fixed to sRGB with confirmation boxes asking if you are out of your mind, and other disclaimers if you try to change it)

[rich apollo]

Thanks, Leonard.