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Serious Question

So... there I am with everything colour managed. I take a photo of something 3D and real - pretty very good.

However, I still have a problem with exposure. I want to take faithful photos of my wife's paintings. I can take them so they are bright and luminous, or I can take them so that they are shadowed and dark. I obviously want something in between but am not happy as to what is RIGHT.

She exclaims 'oh, you've made it look even better than my picture!!' but that is clearly not right. If I drop the exposure, then it does look too, too... something.

I cannot be the first to come to grips with this, so would welcome any suggestions. I do have some ideas, but would rather hold back so as to invite originality.

Thanks for reading this far....

denbigh
 

Michael Nagel

Well-known member
Examples would be nice - preferrably one where your wife said that it is better than in reality and one how you see it.

Generally spoken - expose to the right (I am writing about the histogram) and adjust to brightness/contrast comparable to what you see. Colour is very important, but even more important is the light.
If you only use frontal light, you get the colours, but you lose the structure of the surface.
If the surface structure is important - use some grazing light.
Use the same sort of light for all to avoid white balancing issues.

HTH

Best regards,
Michael
 
I've photographed many paintings and drawings and the whole process is a high level craft (art?) in its own right. And the stakes are higher still because the ego of the original artist is often involved too.

The key I used to eliminate uncertainties about brightness and colour was to include a grey card and Macbeth colour checker in the same frame as the painting or drawing. If final reproduction of the card and checker match the originals then the reproduction of the painting/drawing is as good and unbiassed as your equipment will allow.
 

Asher Kelman

OPF Owner/Editor-in-Chief
I'd use lights from left and right at an angle of 45 degrees and adjust them until the illumination measured with an incident light meter is even. Then one needs a picture of a giant white card taken as a base line for the corrections used with Capture One to make up for uneven illumination and lens cast in MF backs. Essentially one has to make a correction curve for your pictures with the inverse of the picture of the white card with the same illumination.

Bart Van Der Wolf has described how this is done.

Asher
 
So... there I am with everything colour managed. I take a photo of something 3D and real - pretty very good.

However, I still have a problem with exposure. I want to take faithful photos of my wife's paintings. I can take them so they are bright and luminous, or I can take them so that they are shadowed and dark. I obviously want something in between but am not happy as to what is RIGHT.

Hi Denbigh,

I'm not sure I understand your issue. The taking of a (reproduction) image is a pretty much mechanical process. It does not produce a different look, unless you over- or under-expose and correct for that in post-processing. Maybe you mean something else.

Do you have an example to show us, maybe that will help to identify the issue?

Cheers,
Bart
 
I'd use lights from left and right at an angle of 45 degrees and adjust them until the illumination measured with an incident light meter is even. Then one needs a picture of a giant white card taken as a base line for the corrections used with Capture One to make up for uneven illumination and lens cast in MF backs. Essentially one has to make a correction curve for your pictures with the inverse of the picture of the white card with the same illumination.

Bart Van Der Wolf has described how this is done.

Hi Asher,

Yes, correcting for uneven lighting and color cast is one of the roads that leads to better reproductions or image quality in general. Some software will automatically correct for camera lens vignetting and light fall-off to the corners, but with reproductions it is also beneficial to correct for uneven lighting.

The first thing with reproductions is to get the lighting as even as possible, and avoid surface reflections. This is easier with relatively longer focal length lenses, because the lights can be placed at less oblique angles to the surface of the artwork, and due to the larger distance they exhibit less light fall-off. An easy rule of thumb is that you need to place the lights no closer to the sides of the camera as the artwork is wide. Materials with lots of glossy surface structure may need a bit more, or the use of cross-polarization (polarize the light-source with filters and use a crossed polarization filter on the lens) is recommended.

The LCC procedure in Capture One has been changed a bit in Version 7, but the usefulness is still the same. Also a free Rawconverter like RawTherapee offers an LCC capability, and there is an experimental plug-in for Lightroom that apparently offers LCC capabilities.

But the first thing to get right is the light-sources and exposure. As always, that's where it starts. All the rest (color calibration and LCC and post-processing) will allow to get even better results, but if the lighting is poor, then the final results will suffer as well.

Cheers,
Bart
 
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