Hi ARGB 1998 is gamma 2.2. Is it possible you have black point compensation checked for one soft proof and not the other? And were they the same settings (rendering intent etc) used when the conversion to ARGB and Grey Gamma 2.2 happened? Personally I would go back to the original file and do both conversions myself before I started comparing things. When you do a conversion there is a dither option not present in the soft proof so its not clear which your softproof is - (dithered or undithered) (Not that I have ever seen a difference). When you Preview the conversion in Edit >Convert to Profile... is the posterisation present? Best Matthew _________________________________ Matthew Ward matthew@matthewwardphotography.com www.matthewwardphotography.com www.imagebasedlighting.co.uk _________________________________
________________________________ From: Peter Miles <P.Miles@massey.ac.nz> To: colorsync-users <colorsync-users@lists.apple.com> Sent: Sunday, 30 November 2014, 21:58 Subject: Softproof puzzle
Hi List members I don't understand something I have been seeing when soft proofing our staffs black and white images.
When printing on hahnemuhle PhotoRag 308 paper on our Epson9900 printer I use a custom profile to soft-proof the image before printing. The PhotoRag 308 paper profile is a CMYK profile and built in i1Profiler. I use a colorburst RIP.
I have noticed that the soft-proof of our staffs B&W images show posterizing in the deep shadows, when the images they supply are in the Adobe RGB1998 colorspace. But the same image, in Gray Gamma 2.2 space does not soft-proof with the posterizing in the shadows. My understanding is that the gray axis of Adobe RGB1998 IS gray gamma 2.2. So why the difference in the soft proof when the a source file is Adobe RGB1998 vs Gray Gamma 2.2?
NOTE: When I use Photoshop to actually convert the RGB versions of the image to "hahnemuhle PhotoRag 308" CMYK color space, there is no posterizing visible in the shadows of the converted file. So it just appears to be a soft proofing thing, but only with 'RGB' colorspace versions of the B&W images.
Your help with clarifying why this happens would be appreciated. Thanks Peter Miles _______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/matthew%40matthewwar...
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