Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: issa on September 16, 2013, 09:10:50 am
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Hi all
I have been asked to photography hand made tapestry, they are modern, but I am sure they will be one day works of art. There is about 15 of them and have taken about 10 years to complete. Most are about 6 x4 feet and some larger. I have not photographed cloth materials in the past.
I intend using arca an M-line 2 technical camera with an IQ160 with either SK60 XL or Rodie 90 Diagron W.
Would use guys use Tungsten Lighting and adjust the WB in C1 or use Strobes with soft box to ensure even lighting.
For the larger panels would you stitch or go wider such as SK43xl, also there is the challenge of moire where there is large parts of plain material.
Your input is very much appreciated.
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Hi all
I have been asked to photography hand made tapestry, they are modern, but I am sure they will be one day works of art. There is about 15 of them and have taken about 10 years to complete. Most are about 6 x4 feet and some larger. I have not photographed cloth materials in the past.
I intend using arca an M-line 2 technical camera with an IQ160 with either SK60 XL or Rodie 90 Diagron W.
Would use guys use Tungsten Lighting and adjust the WB in C1 or use Strobes with soft box to ensure even lighting.
For the larger panels would you stitch or go wider such as SK43xl, also there is the challenge of moire where there is large parts of plain material.
Your input is very much appreciated.
In our Division of Cultural Heritage Imaging (http://dtdch.com) work we recommend the creation of a custom ICC profile using a professional color target like the 140 patch Color Checker SG. We help our clients with that on a frequent basis.
We'd also recommend the use of a white-reference (a clean white wall, or a large roll of seamless white, crinkle free, or similar) to account for any lighting variation across the subject. You can also use a white-reference to re-even the light after using a ratio'd light source to create a greater sense of texture on the subject which can be important to objects like tapestry.
If you're getting any moire then you are under sampling the original object and the best approach is to increase capture resolution. This of course assumes the only priority is the perfect cultural heritage capture of the original including the underlying threading, and ignores practical issues (like how much you're being paid compared to the amount of work required to shoot at a resolution sufficient to avoid moire and provide accurate capture of the underlying thread, competitive issues, how large a file the client is even able to accept/use, what the use of the capture will be and whether that use supports/benefits-from a huge file etc).
[Single-Shot] vs [Stitching via back movement] vs. [Stitching via pan/tilt] vs. [stitching via subject-movement] all have advantages and disadvantages. A large consideration is how much physical space you have to work with (often our cultural heritage clients have surprisingly little room for their copy stations. With large tapestry and other objects of a textural nature my default recommendation is stitching via back movement with a lens like the 90-SW or 60XL assuming the required resolution can be accomplished without leaving the heart of the image circle.
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Hi Dough
As usual very informative and helpful. The intention was to do a white balance and ICC calibartion, but did not intend on using the 140 patches. Also I was planning to use two ratioed strobe lighting one either side and shoot at f8 with rodie 90m or sk60xl.
You mention white walls or white roll to account for light variation, how about taking an LCC shot instead
My client want to print 30"x20" and sell these as fine art prints for @$300, so resolution is important and I think I will get away without stitching using the 160 back, if stitching required then back movement will be applied.
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Hi,
try to do with and without cross-polarisation. Cross-polarisation (and cross lighting too btw) can sometimes look strange on material with a strong texture.
If the Panel/Artwork is hanging close to the floor, be careful of the reflexions coming back from below. A lot of museums and galleries have a wood floor which reflects some nasty yellow light. I always carry a roll of black paper to put underneath the artwork, if i can't move the artwork.
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You mention white walls or white roll to account for light variation, how about taking an LCC shot instead
I re-read my post and apparently I just truncated my thoughts.
Using a white wall or other clean white reference target (filling the full frame) you would create an LCC to account for the lighting variation. As you know (but other readers may not) you can use this method rather than the traditional plexi-glass-in-front-of-lens method which only accounts for the lens variation.
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I re-read my post and apparently I just truncated my thoughts.
Using a white wall or other clean white reference target (filling the full frame) you would create an LCC to account for the lighting variation. As you know (but other readers may not) you can use this method rather than the traditional plexi-glass-in-front-of-lens method which only accounts for the lens variation.
Also in a typical repro setup the white perspex diffuser will take 3-4 stops of light away if not more (because it's reflective light) so will be hard to compensate for without powerful strobes
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This is very interesting, I am new at photographing artwork and this forum has great information. Can you clarify "LCC" and the use of plexiglass in front of the lens for me?
Thanks,
Jim
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LCC (Lens cast correction) is designed to compensate for colour casts and light falloff caused by Lens movements (Phocus calls this "scene calibration"). You set up your shot then capture a shot with the perpsex in front of the lens which gives the software a shot showing the light variations only that it can use to correct the image. As Doug says you can do the same thing just by shooting a clean white wall.
I did a test once shooting a copy for a friend (think unpaid) and I didn't feel like pulling out more than one light :) I shot a plain white surface lit with one light and used the scene calibration to correct the falloff, worked perfectly.
Hope that clarifies.
Nick-T
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Hi,
try to do with and without cross-polarisation. Cross-polarisation (and cross lighting too btw) can sometimes look strange on material with a strong texture.
If the Panel/Artwork is hanging close to the floor, be careful of the reflexions coming back from below. A lot of museums and galleries have a wood floor which reflects some nasty yellow light. I always carry a roll of black paper to put underneath the artwork, if i can't move the artwork.
I used cross-PL to shoot fabric-based flat art before, and it works pretty well, solves a lot of lighting problems if you have to work on location. Just remember that you can't use diffusers on the light if you have the filters on, as it will depolarize the light again.
Also, be wary of the presence of metal thread or other highly reflective items or materials in use, cross-PL will make these look dull and brown. Worst case, shoot two versions with/without the polarizers and blend in photoshop as needed. Make sure to have two separate profiles for use with and without polarization as their color reproduction is different!
Using LCC to even out the illumination on flat art is the reason I use Capture One, I'd go crazy trying to get it even on-canvas, so to speak.
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Careful how you light it as sometimes with strong directional lighting the regular pattern of the weave becomes over emphasised at the expense of the design.
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Nick - T
It does and thanks.
Do you create a layer with the corrections to "overlay" the image thereby neutralizing the "unevenness"?
Jim
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Do you create a layer with the corrections to "overlay" the image thereby neutralizing the "unevenness"?
Hi Jim,
An LCC correction for each individual image is done in (Raw) linear gamma space, not with post-processing in a gamma adjusted working space. Capture One, but also Raw Therapee (and with a plugin even LightRoom), can handle that almost automatically.
A stitching application can then deal with remaining differences between individual tiles.
Cheers,
Bart
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To all who spend their time helping others,
At this for 46 years (remember the Yashica Electro 35?) and more to learn... thanks.
Jim
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I would rent a Hassey 200MP multi-shot camera and use the HC50 II lens. Cross-polarization is a good idea. Shoot/process using Phocus set to reproduction mode.
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I would rent a Hassey 200MP multi-shot camera and use the HC50 II lens. Cross-polarization is a good idea. Shoot/process using Phocus set to reproduction mode.
Thanks, why would I want to rent a 200Mp Hassey MS, whilst I already have a Phase IQ camera, never mind the cost and learning curve of a new Camera system
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4-shot gives you a sharper image (lens dependent) and a true colour information as each pixel is sampled with RGBG(green for luminance) so no bayer guesswork.
i'm sure the experts from phase will argue over over more pixels and hassleblad over true colour but IME at smaller file sizes (39 and below) the quality jump was significant with 4shot and would certainly take interpolation much better than an equivalent single capture.