articles/Nature/scoreandperformance-page6

The Score and the Performance - part 6 of 1 2 3 4 5 6

Published 01/08/2010

We repeated the test using the gamma slider of the Levels adjustment to check out the influence and ability to detect changes in contrast. This too was variable and showed no bias either way.

Visually the print looked crisper and more tonally separated in the viewing booth than the screen soft proof. Most observers, we feel, would describe the actual print as having more 'quality' than the screen view. The differences between a 'full-colour' and an ABW print were just possible to detect with the prints in hand and were confirmed as different when measured by densitometry (the ABW/Dark print was at 15.8% luminance in the top left corner; the full-colour print was at 14.9% luminance. The file was around 12% luminance). The full-colour print had more density than the ABW print in the shadows but the overall impression of the prints was that they were visually identical when viewed from a normal distance although there was a subtle difference in the highlight tone contrast levels (see graph).

We did manage to detect the difference between the highlight rendering using soft proofing of both colour and ABW/Dark but we would not like to be betting the mortgage on our ability! However, we consistently struggled to differentiate either prints or soft-proof views, even with the images side by side. This is, of course, good news, they were, after all, excellent prints made singly by two routes, of almost equal merit.

On-screen differences were slightly masked by subtle differences in rendering of the actual screen; one print looked warmer at the top but then the result was reversed if the other print was soft proofed at the top of the screen. In hand, the full-colour print looked slightly magenta and the ABW looked slightly greener. In reality the ABW was closer to the base white and the full colour was indeed about 1 Lab point towards magenta.

After a number of hours of testing we came to the conclusion that you can just about soft proof with either the full-colour or ABW profile but that differences in the viewing 'experience' mask any differences between the actual prints made by the two methods.

The aim of this process was to test if it is possible to tonally adjust a print on screen and then create a print that is both accurate and satisfying to the viewer. We often express this as delivering 'no surprises when the print pops out'. Our gut feeling is that this should be possible and that both ABW soft proofing and a good full-colour profile would deliver equal performance. The errors we measured are shown as examples here but may not reproduce with complete precision. In hand, the inkjet prints were readily differentiated at the ±12 level and just about at the ±5 level (on brightness). The level achieved by our testers (nominally ±7) therefore indicates that soft proofing is possible as a control measure but only if care is taken; it would not take much sloppiness for the whole thing to go belly up!

We had to work hard to get to this stage and we are indebted to Toby Herlinger of Fotospeed, who provided us with enough sample sheets to get through our testing. Most of the analysis was conducted on the Canson Baryta Photographique 310gsm paper; it has certainly caught our eye for its delightful quality.

• The Score and the Performance page 1
  
• The Score and the Performance page 2
  
• The Score and the Performance page 3
  
• The Score and the Performance page 4
  
• The Score and the Performance page 5
  
• The Score and the Performance page 6
  

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