8 Replies Latest reply: Sep 5, 2010 7:52 PM by p taz RSS

    How to select the white scanner background

    rlinsurf1 Community Member

      I have the following image (this is a small jpeg version). I need the white background that was the lid of the scanner transparent, but I can't figure out how to select it without getting all the fine detail in the rice paper edge lost. I tired rescanning it against a black background, unfortunately, because the rice paper is so thin, you can see any color you place behind it through the paper itself.

       

      Here's the image (Please note, the background color of the image is almost identical to the background of these posts, so please keep the actual borders in mind):

       

      rice_paper_sm.jpg

       

      And here's a larger version of the file: http://dhnet.us/images/rice_paper.jpg. The original .psd is about a gig, so there's lots of detail there.

        • 1. Re: How to select the white scanner background
          c.pfaffenbichler Community Member

          The scan seems to be fairly bad, the lines in the background are a problem in my opinion.

           

          The best starting point seems to be the B-channel from the RGB-file or the b-channel of an L*a*b-copy with seriously increased Saturation.

           

          But maybe it would be easiest to create a custom Brush-tip, add some randomized Shape Dynamics and paint an edge.

          • 2. Re: How to select the white scanner background
            rlinsurf1 Community Member

            Sorry, can you remind me of how to do that?

            • 3. Re: How to select the white scanner background
              Wade_Zimmerman Community Member

              Try this

               

              Turn the paper over.Spray that side with opaque white with a vey light coats probably two would be good you have to let it dry before the second coat.

               

              Medium gray background, blue or green screen or black backgrounds.

               

              Then duplicate the file and turn it to gray scale  make it high contrast use the black as a mask. Copy it to the color scanned image and you will probably get a really goodreslut a little faether on the edge might be nice.

               

              But I think you have to have it on a darker background.

              • 4. Re: How to select the white scanner background
                rlinsurf1 Community Member

                Can you suggest a good paint to do this?

                • 5. Re: How to select the white scanner background
                  p taz Community Member

                  My 2c on top of excellent advice already here...

                  use a 'greenscreen' technique as suggested by putting a smooth, lightly coloured card over paper on the scanner, because that will let you keep the tiny shadows that define the edge detail after removing the colour of the card using levels.  The idea is that if you have a backing card that it equivalent to 5% cyan and 25% yellow, if you use levels midtone adjustment to remove that much colour in c and y channels, you will end up with the little shadows in the black channel (with a little undercolour), and the main part of the paper effectively almost greyscale.

                   

                  It would be easy to colourise the paper to whatever tone you need.

                   

                  If you are putting this element on top of a coloured panel, you could find a card with a similar colour so that any remaining colour in the delicate areas is compatible with the new background and then you can be more sympathetic with a background removal.  As suggested earlier, making a selection of the background of the fringe should be feathered a little for realism, especially if you are creating your own shadows rather than scanning the existing shadows.

                   

                  If you do a good job of adding the shadows you will get away with murder on the selection of the fringe as it is the shadows that make it work!  I would suggest a photoshop drop shadow (or InDesign but the preview is not good IMHO).

                  • 6. Re: How to select the white scanner background
                    rlinsurf1 Community Member

                    Wow. Can you tell me where I can find that kind if paper?

                    • 7. Re: How to select the white scanner background
                      Wade_Zimmerman Community Member

                      You get it in an art store it is either called white opaque or pro white.

                       

                      You have to be light handed when you spray it. It can be are brushed or you can use the old atomizer technique you know you put the liquid in the jar place the atomizer top on it and lightly blow through the tube and gentle back and forth.

                      • 8. Re: How to select the white scanner background
                        p taz Community Member

                        If you are asking about coloured paper, then your local stationery should have some.  It does not need to be too close, for example if you were using a purple background, you could scan with a lilac or pinky background, remove the open area with 'select color range' restricted to solid area, expand 1 or 2 px depending on image size and feather 1-2 px. Keep the background transparent.  You may wish to add a slight drop shadow.

                         

                        When placing into InDesign, put your background colour in and place the psd file on top and view as high res preview to see how it worked.

                         

                        This suggestion assumes some level of skill with 'select color range' etc, so if you need some hands-on help, I would be willing to do it free for you as a sample job for my blog http://helpme-adobewan.blogspot.com/2010/08/introduction.html where I am looking for interesting small challenges to publish as samples/tutorials.  Hit me up on the blog if you like as explaining in detail here is a bit beyond the scope of this forum...

                         

                         

                        <gratuitous plug>

                        If anyone else has an interesting challenge that is beyond their personal knowledge level, such as colorising old black and whites, I am looking for suitable demonstration/sample jobs to add to my blog.  http://helpme-adobewan.blogspot.com/2010/08/introduction.html