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Author Topic: Which response curve for copy work?  (Read 1264 times)

ComputerDork

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Which response curve for copy work?
« on: September 27, 2015, 12:14:28 pm »

Which response curve do you use for copy work?

I have been using linear since that seems to more closely resemble a scanner than film standard. (Film standard seems to lose detail in light areas such as a cloud in a light blue sky.) But I end up with less saturation.

These issues can be fixed with further post processing but I'm trying to figure out which setting provides the best starting point to lessen the overall amount of work.

(I am mostly photographing paintings.)
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ddolde

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Re: Which response curve for copy work?
« Reply #1 on: September 27, 2015, 12:20:34 pm »

What is a response curve?
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AlterEgo

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Re: Which response curve for copy work?
« Reply #2 on: September 27, 2015, 02:56:49 pm »

Which response curve do you use for copy work?
P1 created linear scientific curve files for repro work that unlike linear curve do not have instructions to paint clipped (or closed to clipped) areas in nice (instead of magenta when green channel is clipped in raw) colors... you can try to rename of of those curves to be able to use it... not sure if that will make any difference if you do not have areas close to clipping though - but you can do experiement
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Doug Peterson

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Re: Which response curve for copy work?
« Reply #3 on: September 27, 2015, 03:21:00 pm »

When doing high-end reproduction work you should use Linear or Linear Scientific and an Object Level Target like the ISA Targets. If using Linear you should be aware there is a slight roll off at the high end of the tonal range, so you should set your exposure based on middle gray and not light gray. This can be useful when shooting higher gloss subject matter and you are not, or can not cross polarize, since a gloss in Linear Scientific can lead to weird artifacts in transitions between blown and nearly-blown tones.

The loss of saturation is because the default profiles in the general purpose version of Capture One are geared toward use with a curve in general purpose photography. If you're looking to match the quality produced by The Getty, Library of Congress, Smithsonian etc or are working with clients looking for FADGI compliant reproduction then I'd suggest Capture One Cultural Heritage Edition which come with bespoke color profiles for cultural heritage imaging (e.g. art repro) which are meant for use with linear curves and also include LAB readouts which can be used to validate the response curve and AOI of the Object Level Target to confirm perfect exposure and perfect linearity.
« Last Edit: September 27, 2015, 03:22:44 pm by Doug Peterson »
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