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Author Topic: SB 54H: white shading files question  (Read 2568 times)

ynp

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SB 54H: white shading files question
« on: January 09, 2008, 05:09:25 AM »

I am a new user of  the Sinarback 54H and I am trying to get used to the back and CS 5.5.1 software. I am going to be using the 54H for copying work.
In  one of the SinarBron press releases I found a claim that white shading file can help to expose the texture and surface details on paintings. I am confused and cannot understand that part.
Can more experienced users explain how it works?
I have always assumed that the surface detail is exposed better with different lighting rates and light directions. What is my mistake?
Thank you,
Yevgeny

http://www.micropubnews.com/publication/ar...id=1875&pubId=1  
QUOTE :
The key to the reproduction solution is the Sinarback 54H multi shot professional digital back. One of the challenges of reproduction is being able to show texture in a painting while providing uniform lighting. Reproduction specialists can now create a white shading file using the Sinarback 54H, which accurately preserves surface details as it evens out lighting. The back is also virtually moiré free. With the Sinar Bron Imaging reproduction solution lighting is no longer a challenge.
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Christopher Arnoldi

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SB 54H: white shading files question
« Reply #1 on: January 09, 2008, 06:35:22 AM »

Whith my SB 54H I use white shading often for reproductions of paintings. Normaly you use 2 lamps  for reprouction work. But then you have double shadows.
When you use 1 lamp, you have 1 shadow but light fall off.

To avoid this you put a white card board over the painting and create a white reference (>object), that correct the light fall off of the lamp. Then you take away the white card board and take the picture with your white shading.

The photograph of the painting shows no light fall off the the corners an the vignetting of the lens is corrected also. The painting has only one light direction.
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ynp

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SB 54H: white shading files question
« Reply #2 on: January 09, 2008, 09:19:51 AM »

Dear Christopher,
Thank you  for your explanation. I am still not very familiar with the CS 5.5.1 and all the capture options (spoiled with the Brumbaer Tools) 8-)
I checked the white shading shooting ( Capture/ Create Scene Reference) with one Dedolight  HMI 575 acute angled light. And it works!
I like CS more and more...
Thanks again.
Yevgeny
Quote
Whith my SB 54H I use white shading often for reproductions of paintings. Normaly you use 2 lamps  for reprouction work. But then you have double shadows.
When you use 1 lamp, you have 1 shadow but light fall off.

To avoid this you put a white card board over the painting and create a white reference (>object), that correct the light fall off of the lamp. Then you take away the white card board and take the picture with your white shading.

The photograph of the painting shows no light fall off the the corners an the vignetting of the lens is corrected also. The painting has only one light direction.
[a href=\"index.php?act=findpost&pid=166096\"][{POST_SNAPBACK}][/a]
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Christopher Arnoldi

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SB 54H: white shading files question
« Reply #3 on: January 09, 2008, 10:16:04 AM »

I like CaptureShop very much, because it is easy to use. One useful thing is that you can dissolve out the curve palette and make it bigger, so you can make really finetuning on the curve.
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thsinar

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SB 54H: white shading files question
« Reply #4 on: January 09, 2008, 08:06:36 PM »

Dear Yevgeny,

Jumping in a bit late (having been on a flight back to BKK), but basically the answers given are absolutely right: with this "White Reference Scene" one can correct up to nearly 3 f-stops fall-off in your scene/object lighting ---> ideal for reproduction work.

Best regards,
Thierry

snickgrr

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SB 54H: white shading files question
« Reply #5 on: January 09, 2008, 09:33:14 PM »

That's pretty cool! No more inverse square law...almost.
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ynp

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SB 54H: white shading files question
« Reply #6 on: January 10, 2008, 04:37:54 AM »

Thank you all for your help!
Yevgeny
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