jad@dayton.UUCP (J. Deters) (05/26/89)
About two or three weeks ago I posted some UPC and 3 of 9 barcode generating programs. After working with a CCD scanner vendor, we determined that the UPC produced was *NOT TO SPEC*. The problem manifested itself as a one-pixel difference between the first guard bar and the second. This is due to PostScript rounding to the nearest pixel. The difference in size was enough to cause the scanner to think it was a different type of barcode (probably codabar) and since the rest of the barcode didn't conform to codabar, it would not read it. This problem is probably very* application specific. We printed the barcode slightly smaller than nominal (but larger than 'reduced'). It also is affected by the location on the page. We were using a very new, very sensitive CCD scanner. And, we are printing on a 300 dpi resolution printer. All these combined to make the second guard bar slightly wider than the first. We are considering some solutions to the problem. We might try using itransform to round the actual location. We may just have to print larger barcodes to 'average out' the differences. If any of you have had similar problems or have good ideas that we might try, I'd really appreciate to hear from you. (Glen 'the Shell Answer Man' Reid, did you catch the hint?) I would like to apologize to anyone who is currently using the code, and I hope to repost a corrected version as soon as we devlop one. I also hope that none of the rest of you have printed up 200 copies of a 34 page, hand laminated UPC book that you just finished shipping. (I would also like to apologise to anyone in Canada or the UK who doesn't like the way I spell apologize.) John Deters MIS/1060 Dayton Hudson Department Store Co. 700 on the Mall Minneapolis, MN 55402