Getting Real Close...

After another week of hard work I have significantly improved the output of JayLight.

For those with FTP access please take a look at the file "JayLight_021909.pdf" in the test_output folder - this is the latest output for the current test file "Visio-JobTracking.pdf.jlt".

I have found the best way to see what's changing and for comparing files is to open them in Acrobat and zoom in to full magnification. The upper imager on the right is taken from the new version. The top part of the image is a "Grab" from Acrobat. The lower portion of the image is a "Grab" from the JayLight output. If you compare this area of the new file to the previous "JayLight_021309.pdf" you will see a significant improvement in the details around the heads of the "blue people". The area of improvement relates to how edges are handled. The SHORT_GB operator mentioned in a previous post has a variety of special cases which I have now figured out.

In particular, when an edge is drawn across a pixel and the bottom or top of the pixel is connected to the previous or next pixel (by the fact that all sub-pixels on the top or bottom of the scan line are "on") special color handling occurs (see the little 4x4 square). On the top the edge would be connected to the previous pixel because all four pixels across the top are "on".

There are various special cases across the top and bottom for the marking color and the what I call the "under color" which is represented by the pixels that are not marked.

There may also be some special considerations for the K color plane but I am still working in this area.

The improvement is also seen in the second image from the 0219 upload seen here on the right.

If you compare this area of the previous (0213) upload you will see a significant improvement. There is still room for improvement around the bottom of the box and along the edges of the large box into which the smaller box is being placed.

There is a second file uploaded with this version call "JayLight_021909A.pdf". This is an example of a converted file from a commercial application (Walgreens.com). (Note: This output is produced in a plant which I believe to be (or was) the largest Indigo installation in the world with 24 HP 5000's in a single room.) This file is the "Kristen & Mike" file. There are may images and also calendar areas in this file. There are still issues in the area of the reverse text on the calendar pages as well as in Kristen's hair where she is pictured next to Mike (as on the thumbnail on the first page). This file is quite large and only represents the first part of the calendar (pages 1-12). The production calendars are 28 pages.

If anyone is motivated please down load this and take a look. I have also placed the original JLT file on the site as well - "50-012775-616.prj_58_0711_1340.pdf.jlt". On page 6 you will see artifacts in the color images (see what I presume to be "Kristen and Mike" on the left and someone else on the right). The artifacts appear only on the CMY planes.

As far as the commerical application of all of this. First off, some of you are interested in this as it is now - which is an "extract" program for accessing the final press-ready JLT data as a PDF. I believe that this version is probably one cycle away from being ready for general commercial release. The basic functionality is currently to extract the image data and, after optional scaling, place it in a PDF. I plan to extend this to include directly generating a JPG or TIFF as well as a PDF - which will be more practical for web applications.

Second, some of you are interested in converting data to JLT. In order to do this I need a perfect understanding of the file format which the current exercise is providing me. Once this is done I will add two more features to the application. First, you will be able to load an image (JPG or TIFF) into JayLight. The second is you will be able to save the output as JLT. I also plan to allow sub-images to be imported. The first real test will be to import a sub image of an address block (say just the K color) and place it on an existing JLT - that way it will be easy to create a simple VDP-type proof of concept.

On another note - this technology was fully developed by me without access to any HP or Indigo technology an a "clean room" style of software development. Someone provided me the file "50-012775-616.prj_58_0711_1340.pdf.jlt" and asked if I could arrange it so that it could be produced on an iGen. JayLight is the result of that effort. I have a complete "process history" of how I decoded the JLT format which I hope to post here at some point in the future. I mention this because everyone interested in this project has raised concern that their "tech" will be unhappy (which unknown complications) if this program somehow "interferes" with their press.