6 Replies Latest reply on Dec 23, 2012 6:12 PM by Noel Carboni

    Filtering and enhancement possibilities, old image

    PiperByrne

      Hello,

      I have a question that relates to a digital image that is of an old original B/W photograph. It is a little complex so please bear with me.

       

      The image is of an old, plain page of a book found by Police some 65 years ago, in it's orginal form the police had noticed what appeared to be indentations or very feint writing on this page and used graphite powder to highlight their findings and then went over the highlighted areas with what appears to be an early felt tip pen. This was then photographed and an image produced.

       

      Code_GF_Base.jpg

       

      The intial image itself is quite small about 400 X 400 px.

       

      It shows 5 lines of hand written characters with additional hand drawn lines.

       

      Here is an example of a close up of the 'sharp end' of the two crossed lines in the centre of the page:

       

      xline1_cp9gcat_sml.jpg

       

      Here is that image reversed:

      xline1_cp9gcat_reversed.jpg

       

       

      When I examined the image in more detail I noticed that the actual characters and lines were not simply black markings but in fact had various shades ranging from grey through to black within them.

       

      I turned the image negative and it showed up what appeared to be smaller letters and numbers behind the initial blackened markings and lines. I have done some basic filtering and have managed to improve on the appearance but only a little.

       

      The questions I have are these:

       

      1. Are these real markings or are they some kind of digital noise? Most of the letters and lines on this page show signs of letters and words beneath the drawn over markings. (I have done a lot of research about micrography and such miniature writing does and did exist at the time and in fact has been around for 4000 years or more)

       

      2. Is it possible for me to 'strip away' further layers of lighter coloured pixels to sharpen the markings that appear to lie beneath the overdrawn characters and lines?

       

      3. This being so, what steps or processes can be used to achieve better clarity and hopefully a larger image.

       

      I hope I got that right and it makes at least some sort of sense

        • 1. Re: Filtering and enhancement possibilities, old image
          Mylenium Most Valuable Participant

          Nobody can know with knowing the original and 400px is simply not enough resolution for any serious forensics. If there is any microscopic writing, it would be belnded down to clumps of 2 or 3 pixels at most, making it impossible to discern any letters. And in your case it could simply be the paper structure, anyway.

           

          Mylenium

          • 2. Re: Filtering and enhancement possibilities, old image
            PiperByrne Level 1

            Thanks for that information it's much appreciated. I neglected to mention that the original digital image was 400DPI, I don't know what if any difference that makes.

             

            If I may ask you another question, micro writing as the name suggests is extremely small, an example would be Lincoln's entire Gettysburg address written on to a strand of human hair some 3.5 inches in length. This was done by a man called James W. Zaharee in the 1930s. Do the same rules apply given the tiny size of the writing and the 400 DPI image? I simply don't have the experience to make that call but I had a thought as a result of your advice that I could experiment by creating an image with micro writing and at 400 DPI, draw over the letters with a felt tip or similar and see what happens. Do you think that would be valid?

            • 3. Re: Filtering and enhancement possibilities, old image
              Noel Carboni Level 8

              Is it a certainty that there is microscopic writing here?  Frankly it just looks like overenhancement of the varying amounts of pigment deposited because of the texture of the material it was written upon.

               

              Perhaps the scanning can be done at higher than 400 pixels per inch if you're trying to derive ultra-tiny detail.

               

              -Noel

              • 4. Re: Filtering and enhancement possibilities, old image
                Gernot Hoffmann Level 3

                (confirming Noels opinion)

                The original image, as posted here, has 1802 x 1440 pixels, a fairly good

                scan in my opinion. There is nowhere any evidence for micro writing under

                the marked text - if so, then we should expect such hidden hieroglyphs

                as well at other locations.

                 

                The next step should be the deciphering of the enigmatic message -

                that result would be interesting, IMO.

                But it's already too late - referring to the apocalypse...

                 

                Best regards --Gernot Hoffmann

                • 5. Re: Filtering and enhancement possibilities, old image
                  PiperByrne Level 1

                  Many thanks Gernot,

                  Quite right I had entered the wrong dimensions, all comes from doing too many things at one time.

                   

                  I have examined other letters and have found characters and numbers in various locations beneath letters as well as on the main body of the scan. My problem has been enhancing the images found to a level that they become sharper and easier to view.

                   

                  If I may ask, given that the main image is at 400 DPI and I find traces of other markings beneath a letter is it then possible to remove pixels of different shade to enhance what is found?

                   

                  Here's an image which I think shows a result:
                  line4_C_Jestyn.jpg

                  This is the last letter in the 4th line, 'C'. I make this to be JESTYN with the letter N partially concealed behind the serif/rocket at the bottom right. This is either correct or an amazing coincidence that these 'letters' showed up, as a person with the nickname JESTYN was closely associated with the case.

                   

                  Your comments on the message are correct, it would be great to decipher its meaning. The thoughts have been that it is a one time pad encryption which would make it just about impossible to decipher without the key word or phrase.

                   

                  Happy to produce other images with better visibility but please bear in mind that the problem I have is making them clearer to see.

                   

                  I must have missed the apocalypse, too busy at the time, I'll try to make the next one

                   

                  Best Regards and thanks

                   

                  PiperB

                  • 6. Re: Filtering and enhancement possibilities, old image
                    Noel Carboni Level 8

                    Try using a Curves adjustment layer and altering the curves to see if you can increase the contrast greatly between shades that are close together.

                     

                    -Noel