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Author Topic: Turning layers into channels  (Read 11670 times)

Mark D Segal

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Turning layers into channels
« Reply #20 on: September 23, 2009, 07:53:56 am »

Quote from: papa v2.0
hi


just did this today from the 68mb file
(aside from the matlab exercise in image registration, im more interested in colour rebuilding methods)

i think i need to contact the LoC as to the method of digital capture. this is an intriguing experiment.

can we reproduce the capture effect from glass plate negatives?
can we determine the filtration used based on the unknown bgr separations?
can we determine the white source of the projections of the tri negatives?
if i could get any of this info i might be able to try run it thru ciecam02

 i think  basically we have a camera raw file from c1900

any ideas any one?

This is pretty good. Where did you get the 68MB file from? Can you tell us the specific steps you used to produce this?
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Mark D Segal (formerly MarkDS)
Author: "Scanning Workflows with SilverFast 8....."

Mark D Segal

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Turning layers into channels
« Reply #21 on: September 23, 2009, 07:55:11 am »

Quote from: Jeremy Payne
Here's my first pass ... this is fun!

[attachment=16764:1_3.jpg]

Also pretty good Jeremy. Likewise, where did you get the original file and what steps did you implement to get this?
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Mark D Segal (formerly MarkDS)
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Jeremy Payne

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Turning layers into channels
« Reply #22 on: September 23, 2009, 08:38:29 am »

Quote from: MarkDS
This is pretty good. Where did you get the 68MB file from? Can you tell us the specific steps you used to produce this?

Starting with the list from the exhibition ... http://www.loc.gov/exhibits/empire/object.html ... I copied the name of the image - in this case: 'Group of Jewish Children with a Teacher'

I went here ... http://lcweb2.loc.gov/pp/mdbquery.html and searched for the text.

Following the results leads to this: http://memory.loc.gov/pnp/prok/01800/01861u.tif  ... the hi-rez B&W triptych.

I opened in ACR and did a little sharpening, opened in aRGB and zoned out the three areas of the positive B&W and made 3 individual aRGB tiffs.

I used AutoPanoPro to align them in a planar projection.  I saved them as individual 16 bit tiffs.

I opened the files in PS ... created a new, blank aRGB image ... copied the b/g layer from each file into the appropriate channel on the channels pallet of the blank file and re-touched from there.

It was easier than I thought it would be.

I'm gonna work on other methods of alignment.
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Jeremy Payne

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Turning layers into channels
« Reply #23 on: September 23, 2009, 08:47:53 am »

Quote from: MarkDS
Also pretty good Jeremy.
Thanks!   I need to work on the alignment ... APP gave it too much distortion.  I will work on that aspect next ...

As a comparison to mine, here is the image as re-constructed by the LoC:



... and mine:




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Mark D Segal

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Turning layers into channels
« Reply #24 on: September 23, 2009, 09:59:47 am »

Thanks Jeremy. Nice work. Compares well with LoC, except for that bit of distortion you are working on.
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Mark D Segal (formerly MarkDS)
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Mark D Segal

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Turning layers into channels
« Reply #25 on: September 23, 2009, 10:01:36 am »

Oh - and to copy the Background into the channels of the Blank doc - did you use Apply Image for that step?
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Mark D Segal (formerly MarkDS)
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Jeremy Payne

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Turning layers into channels
« Reply #26 on: September 23, 2009, 10:22:33 am »

Quote from: MarkDS
Oh - and to copy the Background into the channels of the Blank doc - did you use Apply Image for that step?
didn't need to ... just regular copy and paste.
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Mark D Segal

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Turning layers into channels
« Reply #27 on: September 23, 2009, 11:38:22 am »

Thanks Jeremy.
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Mark D Segal (formerly MarkDS)
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Jeremy Payne

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Turning layers into channels
« Reply #28 on: September 23, 2009, 04:48:29 pm »

Here's the 'final' take ... whatever that means.  

I leveled it and corrected the distortion introduced in the alignment, cropped it square and did some more retouching.

Overall, I'm very pleased with how this came out ... I'll definitely be doing more and printing them.

Anyone have any suggestions for the paper?  I have an Epson r2880.

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Mark D Segal

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Turning layers into channels
« Reply #29 on: September 23, 2009, 07:55:28 pm »

Fine result Jeremy.

As for paper, it depends on what "feel" you think is right for these images. Let us recall that the originals were projected, so the whole print business wasn't how these images were "purposed" to use contemporary lingo. The essential choice is between matte and glossy (various flavours of each) and you undoubtedly know what the trade-off is. One is nice and artsy and the other has great DMax. I'd suggest you try a print on Ilford Gold Fibre Silk and another on a nice matte photo-rag paper and make a visual/tactile assessment of which medium is a better "fit" for the character and tonal qualities of the images.
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Mark D Segal (formerly MarkDS)
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papa v2.0

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Turning layers into channels
« Reply #30 on: September 24, 2009, 03:18:03 pm »

hi

I got the 68meg files by searching the archive
eg http://lcweb2.loc.gov/cgi-bin/query/D?prok:19:./temp/~pp_JoqR::

and then click on the triptych wich will take you to another page with the links to the different files.

I cut and pasted each frame into a a new rgb file as jermy outlined except that i opened an untagged rgb file and eyeballed the registration.

i then assigned a profile of my my choice.
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JeffKohn

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Turning layers into channels
« Reply #31 on: September 24, 2009, 04:52:34 pm »

Interesting thread. For alignment, I think you could use Photoshop CS4 if you have it. Drag two of the images on top of the third as layers, and then use the alignment feature in CS4. This would avoid the warping done by a pano stitcher, and then you could copy paste them into the individual channels of a new document.
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Jeff Kohn
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Jeremy Payne

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Turning layers into channels
« Reply #32 on: September 24, 2009, 04:59:30 pm »

Quote from: JeffKohn
Interesting thread. For alignment, I think you could use Photoshop CS4 if you have it. Drag two of the images on top of the third as layers, and then use the alignment feature in CS4. This would avoid the warping done by a pano stitcher, and then you could copy paste them into the individual channels of a new document.

I did try that as well (CS4)  - but for whatever reason, APP worked better - less "CA" and edge halos.  I bet it depends on the image.
« Last Edit: September 24, 2009, 04:59:49 pm by Jeremy Payne »
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Pete_G

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Turning layers into channels
« Reply #33 on: September 28, 2009, 09:35:20 am »

Quote from: Jeremy Payne
I did try that as well (CS4)  - but for whatever reason, APP worked better - less "CA" and edge halos.  I bet it depends on the image.

Jeremy,

Good thread. How did you get good alignment between the layers, I tried with APP but the kid to the right of the teacher moved between exposures, did you manage to get APP to fix this for you?
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