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Scanning processPosted: Tue Feb 17, 2015 10:52 pm
|Discuss scanning / editing / stitching techniques here.|
||Posted: Tue Feb 17, 2015 10:55 pm|
Frank Cifaldi from lostlevels & http://gamepreservation.tumblr.com told me of his process that he adapted from Andrew Perti.
this is the filter I use for descreening http://www.descreen.net/eng/soft/descreen/descreen.htm
I always scan at 600ppi or higher, and then resize down to 300ppi
600ppi, descreen, resize
when I scan I turn ALL scanner software shit off. no automatic descreening, color correction, etc.
and then the only thing I do besides descreen is set the black and white levels
so the best method for this:
make a copy of the image
find an area of the copied image that you believe the printer printed as "pure black"
magic wand that area to select it, filter > blur > average
now that area is all the same color. repeat this for a pure white section
layer > new adjustment layer > levels
select the black eyedropper on adjustment layer, click it in the averaged black area
repeat for white
duplicate that levels layer to the original image (the one you didn't do any Averaging on)
if you average out the color of something that is black, that average color is, in theory, black
if you're monitor's any good you can see some good colors from this process here http://gamepreservation.tumblr.com/post/108855176394/gamefan-april-1999-volume-7-issue-4 and here http://gamepreservation.tumblr.com/post/106965022454/heres-a-rare-promotional-comic-book-for-hudsons
if you credit me though maybe you should say it's adapted from this guy's methods https://twitter.com/AndrewPerti
he goes a little crazier than I do
maybe I should just write this up somewhere
it's a compromise between automated levels and manual methods that
take an unreasonable amount of time to do right
it's good enough for me. also it's its own layer on the original image, so you can always go back and tweak it
I think adjusting hue and saturation is adding information to the scan that isn't on the original image
PS: The attachment is comparing an extract of the scan found here
http://www.smspower.org/forums/files/040_b_523.jpg (left side) with his process.
||Posted: Wed Feb 18, 2015 8:34 am|
|I'll see what my process does to that image... The example above seems excessively sharpened to me.|
||Posted: Wed Feb 18, 2015 8:43 am|
|Sorry, to clarify the two images above were scanned separately. I don't think you can 'recover' the right image from the left image.|
||Posted: Wed Feb 18, 2015 9:07 am|
OK, that's good to make clear. Let's try to produce examples from some common source images showing typical issues (screening, moire, etc).
I tend not to blow out the contrast (for whitest whites and blackest blacks) because of the information loss. It's a matter of taste, though.
One task I'd like to automate is very fine rotation by selecting corner and edge pixels, then have software determine the bounding rectangle and rotate and crop exactly to it, possibly resizing simultaneously to avoid sampling error accumulation. I'm pretty sure this doesn't exist in regular tools.
Another one is correcting skew caused by the scanner head moving while imaging. Where we have known 90° features (boxes, grids), it should be possible to unskew automatically. Photo oriented software will never do this because it's not relevant to photos.
||Posted: Wed Feb 18, 2015 12:35 pm|
Here's a raw high res scan of that Alf prototype title screen.
||Posted: Wed Feb 18, 2015 12:38 pm|
Here's my attempt at cleaning it up. I used edge preserving smooth on the image - it's noisier than the descreen plugin mentioned above, but I prefer the sharpness it produces. I also corrected the rotation (1.5°), did some colour correction on the yellowed paper and then equalised the histogram to get more contrast without truncating the dynamic range. Also, JPEG for size.
||Posted: Wed Feb 18, 2015 12:56 pm|
|I'm not sure actually about removing the printing artefacts. (Not sure what's their name). I'm talking about seeing the colored patterns that compose the print. It just seems more real seeing them. Do we need to aim at recreating raw-screenshot quality when looking at the real printed one doesn't look like that.|
||Posted: Wed Feb 18, 2015 1:54 pm|
|That's apparently called screening. I tend to try to reduce it because it plays havoc with JPEG compression, but usually just when preparing an image for the Web - I'd always keep the original scan stored losslessly.|
||Posted: Sun May 17, 2015 10:07 pm|
Longtime lurker of this great community.
Thanks for the shout out, Frank and Bock.
Here is a scans thread I've been maintaining for a bit now: thecoverproject.net/forums/index.php?topic=16138.0
A video series detailing each step of the process may materialize one day. In the meantime, your suggestions, feedback, and questions are welcome.
Edit: Here are a few quick GameGear samples for this site's collection if you like: