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Scanning/copying large prints

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  • Scanning/copying large prints

    I may be getting a print that is larger than my scanner can accomodate,
    (Epson Perfection 2450). The options, as I see it, are: Scan portions of the print and try to use Photomerge, (Photoshop CS). Copy the print with a digital camera, and bring the print to a facility that has large enough scanner.

    Comments on the best way to go? Advantages/disadvantages of each option?



  • #2
    Hi Ken,

    I had to scan prints larger than my scanner only a couple of times .... and I always did it the same way (scanning different portions).

    I tried the digital reproduction of an old print only once (textured paper), but not disposing of the appropriate lighting tools, the result I got was simply terrible .... mind you..... if I had to make a living out of taking pictures .... I would have starved to death a very looong time ago ....

    If you decide to go for the 'portions scanning', one word of advice from Katrin Eismann's book:

    "When scanning large print pieces or prints that are larger than your flatbed scanner platen, do not change the print orientation by rotating the pieces. That will vary the reflectance of the paper texture between the pieces, making them difficult to merge"


    • #3
      Thanks Flora,

      Yes I do remember that caution about print orientation in Katrin's book. I have scanned a larger print in two sections and married them up in Photomerge manually, but have not tried a four-section scan. I need to do that to see what the issues are. If anyone else has thoughts on this, it's appreciated.




      • #4
        I have scanned large photos several times using an Epson 3200 and PhotoShop 7.0.

        I keep the orientation the same and provide overlap. I merge the overlap by using Transform/Rotate in PS. First, I line up homologous pixels in both layers and move the rotation point to this area. Then, I rotate one layer in Difference blending mode to ensure registration.

        Sometimes, slight touchup is necessary to blend the brightness of the seam. In these cases, I use an Overlay layer, painting with grey of about 65 or 35 per cent with low opacity as the case requires. It helps to have individual layer sets for each piece set to "normal" instead of "pass through" with each set having its own overlay layer.
        Last edited by ExclamPt; 04-20-2004, 12:59 PM.


        • #5
          I've scanned large photos needing to be scanned in 6 pieces. Keeping the orientation the same is key. Depending on how big the image is, the cover may get in the way. If so, simply remove it. Also, keep the scanner settings the same over the course of scanning all of the sections. You don't want the scanner changing settings on you or you'll have to do a lot of touch-up to get all of the pieces looking the same in terms of contrast, color, etc.

          You will find that the edges of the scan are darker b/c of the slight lip around the edge of the glass. You probably want to crop these out of your scan to begin with, but it's easy to remove them after the fact as well.

          I have found it difficult not to rotate (slightly) the photo when scanning such large ones (esp. if the photos are cut into an oval and you don't have straight edges to line up on the scanner.) This isn't too hard to correct back in PS though.

          I haven't yet installed CS and regularly scan 12x12 images in four pieces, then stitch together with all of the scanned pieces on different layers. I work with lining up one section at a time. I change the blending mode of the top layer to difference, then use Edit>Transform (if necessary to rotate) to get everything to line up. (With the layer in difference mode, everything will turn black once it's lined up.) Then change the layer back to Normal blending mode and add a layer mask. Use a soft brush to "erase" the hard edges. Also, even with the precaution of keeping the scanner settings the same over the course of all of the scans, you may find that some sections are lighter than others due to how close to the glass they were, etc. You can touch these areas up with adjustment layers or a new layer in overlay mode where you paint (at low opacities) with white to dodge (lighten) or black to burn (darken).

          All of my verbosity makes this sound a lot more complicated than it really is.



          • #6

            All of that makes perfect sense, thank you!

            What I am having trouble with is with the sections. Each is a different file.
            Let's say section 1 is the main section, section 2 I want to marry up with section 1. When I copy section 2 and paste it into section 1 it will only paste within the confines of section 1's borders. How do I stitch section 2 to the right edge, (allowing for overlap), to section 1?

            What am I doing wrong




            • #7

              Ah yes - forgot about that key piece of info. You'll need to enlarge the canvas! Choose one of the corner pieces (I typically choose the upper left), then Image>Canvas Size... Specify a size slightly large than the original photo. (Specifying a slightly larger size gives you room to work with; you will crop the whole thing later after you've stitched everything together.) Be sure that you click on the corresponding corner of the "anchor" in the canvas size dialog box or the canvas will increase on all sides - not what you want in this case.)

              The other option is to create a completely new document that is the size (or slightly larger) of the original photo. Then copy in each piece. I personally like enlarging the canvas of a corner piece, but if it is slightly rotated, then the entire stitched image will be slightly rotated as well.



              • #8
                You're a dear! Many thanks.



                • #9
                  Glad I could help.



                  • #10
                    Sounds like you've got it under control but I thought I'd chime in anyway... just feel like typing I suppose.
                    Anything we can'y scan in one piece we shoot with a camera, digital if the output size is under 22" or 4"x5" film if bigger than 22". We scan the film on an Imacon CCD scanner to digitize.


                    • #11
                      Talk about making work for yourself

                      I would by all means find a digital camera that will produce a file of the size you need. If you do not have one, see if one of your local photo studios could produce the file for you. If you figure what your time is worth (on a per hour basis) you would most likely save money by doing it this way.

                      The second best way is the film camera and scan the neg.

                      Ya, I know that you could do it in sections, put them together in PS, do all the work to make it match, and when it comes out looking pretty good, you can be proud of yourself.

                      But just because it can be done, is that a good reason to do it??????
                      If you are doing this to make a living, time is money. If its a hobby and you are just beating your head on the wall to find out how good it feels when you stop, then go ahead...........



                      • #12
                        Actually, since I live outside of town it would take me more time to drive to a lab, drop off the photo and drive back than it would for me to scan the photo in 4-6 pieces and stitch them together (not to mention the return trip to the lab to pick up the digital image.) Same problem with using a film camera, since I'd have to get the film developed.

                        So that leaves a digital camera. Yes, I've used my 5MP digicam to get photos into digital format, but I feel I get better results scanning (unless the image is heavily textured). And since I do a lot of scanning of 12x12 images (in 4 pieces), I've gotten really fast at stitching. Hence that's my preferred method these days.

                        To each his own.



                        • #13
                          A camera has geometrical distortion

                          Good excuse, "feel like typing"

                          A digital camera can be an excellent "scanner" if you can do it all in one piece, but unlike a scanner, a digital camera (or any camera) will always have barrel or pincushion distortion, unless you're at that magical focal length where everything is right. So that's also one concern.


                          • #14

                            I think Rexx and Jeaniesa have valid points. As Rexx has suggested, I've not had much luck stitching digital copy photos together because of optical distortions. A perfect flat-field lens on a digital camera is not a common thing.

                            And using a digital camera to copy a large image in one fell swoop may result in a digital image with resolution less than that achieved by scanning in pieces.

                            Janiesa seems to have good experience in this area. It's a problem many of us face at one time or another. Might I suggest a tutorial? I'd be willing to create one with Janiesa's help.


                            • #15
                              Originally posted by ExclamPt
                              Might I suggest a tutorial? I'd be willing to create one with Janiesa's help.
                              Now that's one great offer! Anxiously waiting