Re: Soft-proofing discrepancy (?) [was: Softproof puzzle]
Hi Martin and Matthew No, I don't think it's 8 bit issue or a dithering issue or black point compensation. I did the following test 1: I created a new document - Adobe RGB1998, 2000x500 pixels, 16 bit, In photoshopCC 2: Filled the document with a gray ramp, with no dithering, black to white, from from one end to other. 2: Duplicated the document 3: Converted the Duplicated document to Gray Gamma 2.2 4: Soft-proofed both Gray ramps : Hahnemuhle308 profile (profiled as cmyk), RelCol, BPC = on, Simulate paper white = on Result: RGB gray ramp show posterizing in shadows. Gray Gamma 2.2 Gray Ramp shows smooth shadow transition Viewing on EizoCC241 Monitor And... While I see the banding in the soft-proof of the RGB file, the banding disappears when I actually do a Profile To Profile conversion into the printer colorspace. Further, the soft-proof* of the converted file now matches the soft-proof of the Gray Gamma 2.2 gray ramp file. *[Hahnemuhle308, Rel Col, BPC = on, Simulate paper white = on] Regards Peter Miles
Hi there does appear to be a bit of a oddity in the Adobe soft proofing at the near black (or a general oddity in the way printer profiles are built). When you convert to a printer profile in Edit > Convert to Profile... (in Photoshop CC), the Preview does not appear to match the result (near black). I have checked with 3 different profiles (2 Epson, 1 Hahnemuhle) and they all appear to exhibit the same discrepancy to a greater or lesser degree (possibly most severe with Absolute Colorimetric Rendering?). It is, as Peter initially pointed out, most apparent with grads which posterise with soft proofing but are smooth on conversion. Could others confirm? 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 List <colorsync-users@lists.apple.com> Sent: Friday, 5 December 2014, 6:20 Subject: Re: Soft-proofing discrepancy (?) [was: Softproof puzzle]
Hi Martin and Matthew No, I don't think it's 8 bit issue or a dithering issue or black point compensation.
I did the following test 1: I created a new document - Adobe RGB1998, 2000x500 pixels, 16 bit, In photoshopCC 2: Filled the document with a gray ramp, with no dithering, black to white, from from one end to other. 2: Duplicated the document 3: Converted the Duplicated document to Gray Gamma 2.2 4: Soft-proofed both Gray ramps : Hahnemuhle308 profile (profiled as cmyk), RelCol, BPC = on, Simulate paper white = on Result: RGB gray ramp show posterizing in shadows. Gray Gamma 2.2 Gray Ramp shows smooth shadow transition Viewing on EizoCC241 Monitor
And... While I see the banding in the soft-proof of the RGB file, the banding disappears when I actually do a Profile To Profile conversion into the printer colorspace. Further, the soft-proof* of the converted file now matches the soft-proof of the Gray Gamma 2.2 gray ramp file. *[Hahnemuhle308, Rel Col, BPC = on, Simulate paper white = on]
Regards Peter Miles
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On 9 Dec 2014, at 08:42, matthew ward <matthew@matthewwardphotography.com> wrote:
Could others confirm?
That’s always been the case with every version of Photoshop that I can remember. We use a lot of CMYK profiles with custom K ramps and these never preview correctly in Photoshop. Operators are instructed specifically to ignore the preview as the shadow areas are rendered poorly. -- Martin Orpen Idea Digital Imaging Ltd
Hi Martin and Mathew Thanks for confirming that. I thought it might be me doing something I shouldn't. What strikes me as odd, is that if the B&W image is in a true grayscale colorspace ( eg Gray Gamma 2.2) then the soft proof of near blacks looks very good with these profiles. Why would the colorspace of the source file make a difference? Given that Grayscale pixels in gray gamma 2.2 and AdobeRGB 1998 are essentially the same? (or are they?) Thanks Peter
participants (3)
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Martin Orpen
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matthew ward
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Peter Miles