Re: fine art reproduction questions
Re: fine art reproduction questions
- Subject: Re: fine art reproduction questions
- From: Ben Goren <email@hidden>
- Date: Sun, 2 May 2010 09:47:51 -0700
On 2010 May 2, at 8:58 AM, neil snape wrote:
> on 2/05/10 17:37, Ben Goren wrote :
>
>> I don't do copy work any longer.
>>
>> No offense, but I think this has become pretty obvious from the rest of your
>> responses.
>
>
> I don't take any offence to your posts at all.
>
> I do question the quality of any copy work done with a Canon Dslr using a
> 50 mm lens. Nothing has changed in doing copy work sorry to say of finding
> the right solutions.
First, it's not any 50; it's the Canon 50mm f/2.5 Compact Macro. At f/8 and avoiding the extremes of the frame, its quality is all but indistinguishable from the Canon 180mm f/3.5 L.
And, as I wrote earlier, that system is capable of making ~500 ppi images of 9" x 12" originals. A larger format will do better, sure, but we're already well into the realm of needing a loupe to tell the difference.
For larger works -- again repeating myself -- get your desired input ppi by adjusting your subject-to-camera distance (and maybe using different lenses), make multiple exposures, and stitch them together. A larger format wins in terms of speed and ease-of-capture, but the end result is the same (and the equipment used *much* less expensive).
So, unless you've got deep pockets or your volume is such that you need a faster workflow, you're much better off spending your money on lighting, a computer powerful enough to not take forever to process really large files, and the like.
> But as I said I don't do copy work, and if I did I would do what was
> necessary to have the best I could could from what I have or use better
> equipment to do so. If you really believe that a Canon Dslr is providing you
> you flawless files with what you assume to be a linear file, then you are
> avoiding the limitations of what you are using.
Not only do I not assume it's a linear file, I've had to do a *lot* of experimentation and tedious work to reliably create a linearized file from RAW to feed to the profiling software.
I'd like to use Canon's DPP, but there's no good way to set white balance. Until they fix that -- and I have reason to suspect that it's on the radar of Canon engineers -- I'm using Adobe Camera RAW. If you use the Camera Faithful DNG profile, set all the sliders to their zero (not default) position, and use a linear tone curve, the result is surprisingly close to a colorimetric match. For non-critical work, it qualifies as ``good enough.''
I'm in the process of building a DNG profile to improve upon that. Adobe's DNG editor is miserable; it gives no readout of the output color. Still, one can use the Digital Color Meter that ships with OS X to get closer than the Camera Faithful profile. The last one I built is better, but there's still plenty of room for improvement. And, no, the ``auto build a DNG profile from a ColorChecker'' function doesn't cut the mustard. It's a lot worse, in fact. Indeed, if I were going to develop the worst possible target to use for that sort of a task, it would closely resemble a ColorChecker.
So, wether you use the Camera Faithful profile or a hand-built one that's better, the rest of the process is the same. Image your target of choice -- more on that in a moment -- and save a TIFF. Feed the TIFF to your favorite ICC profiling software; mine is ArgyllCMS. That gets you an ICC profile specific to that combination of camera, lens, lighting, post-processing workflow, and all the rest.
Shoot the art using everything else identical to whatever you did for the target. Apply the ICC profile you just created, convert to either your favorite working space for further editing or directly to your printer profile, print, and admire the results.
As for what target to use? I'm not happy with anything on the market, so I'm in the process of making my own. It'll have the 24 ColorChecker patches, made from paints matched at the local hardware store. It'll have another dozen patches of the pure colorants the paint store uses, another dozen patches selected and matched from a Munsell gray scale, and another dozen patches of Golden Fluid Acrylics that have ``interesting'' spectral characteristics (mostly near the spectrum locus with a couple oddballs thrown in that are unlike anything else I've come across so far in this quest). It'll have a couple hundred patches generated by Argyll and printed on an iPF8100. And, lastly, it'll have a white patch made from PTFE thread seal tape and a black trap.
It's perhaps overkill, and I'm not especially looking forward to the tedium of making it, but it picks the best bits of everything else I know about and addresses the shortcomings of each as best I can.
Cheers,
b&
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