Thanks Stuart.

In most cases you might not need to apply Bar Width reduction but we are printing barcodes that are quite small (we are trying to print a code 128 that is 30mm wide).

As we're printing quite a small barcode we've had to apply BWR to get the barcodes to print out and get an A reading on our Litho offset presses and on 3 types of digital (HP indigo, Xerox iGen and a small Oce press).

I tried your code (with my 15 digit barcode in) and at best I get a C, when I use the scale function to scale it down to the size I need.

I'm waiting for the results from the digital print press print outs so I can see what the spread is like on the barcodes... I can get away with a B - but would rather have an A.

I've just scanned the tests we've done from the digital press and we're getting 35% Bar gain which is meaning we're getting a D reading.

Are there no press talk options to thin down each bar?

There is a bar width adjustment for UPC/EAN codes, but reading the specification for C128, I can't find any mention of bar width reduction for these codes.
I found the spec here GS1 barcode spec .

Do you have a different spec?

Hi Stuart,

The spec is not really relevant as I dont want the actual printed document to have the barwidth reduction on... If we have a bar that is 2mm wide then when I Print it digitally with 35% bar gain it is going to become 2.7mm wide (and eat up some white space)... so if I thin that bar down to 1.48mm when it's printed and it adds the 35% bar gain then it will come out at 2mm wide again and scan correctly.

Danny

I don't understand where your 35% bar gain is coming from.

At 600dpi a 2mm bar is about 48 pixels wide and 35% of that is another 16 pixels.

Does it fatten every line, character wtc by 35%? What does it do to images?

I can't see any way of using the PP barcode routines to do what you want. You would need to code your own barcode routine in presstalk.

Hi Stuart,

forgive me but I do not know what your background is so if the below is obvious to you then please dont be offended.

The simplest way to describe it is get a fountain pen and touch it to a bit of paper... the ink will spread slightly.... the same happens when you put wet ink on card... we get some dot gain

Our barcode scanner is reading 35% dot gain... so on average the dots are spreading by 35% when they hit the card.

If this was being manually originated then the user might put a white stroke on it to narrow the black lines to compensate for the ink spread. - most cases we dont do this as we dont always need to get an A/B grade... but this project calls for it.

The dot gain is applied to all the objects but as it's applied evenly then it's not an issue - as it's not measured like a barcode is.

Danny

Stuart.

Thanks for this - you've obviously put lots of work in on it!!

The bar width reduction works perfectly and I can get it down to how I need... but i'm having 2 issues with your code... the decoabailty is failing on 2 of the pairs in the barcode and it's adding extra characters on when it switches to Sub set A - they may be related issues.

If I use barcode 123260789002267 then when I scan it it reads back 12326078900227122 (the 1 part of it reads back in superscript)

If a generate a dimensional analysis report it reads the barcode back as

StartC 12 32 60 78 90 02 27 F1 22 72 Stop

where as a normal barcode reads back as

StartC 12 32 60 78 90 02 27 SubsetA 6 Nul Stop

There seems to be some issue with the check digit.

The 10 digit barcode you provided does not have the same issues.


Thanks for everything so far
Danny

Danny
Whoops! Well I said I couldn't test it.

I used the wrong symbol code - instead of 100 for "switch to subset A" I had 102 which is "function 1".
Put that right and I reckon it will be fine.

Find the lines and replace them by I will edit my main post to correct it.
regards
Stuart

Thanks Stuart,

I actually looked at that bit (which is a good sign that I am starting to understand the code)

The only other issue I had was I had to change

define(&baradjustmult,measure,0.81)

to

define(&baradjustmult,measure,1.0)

It's great to have the option but it was damaging the decodability when used in conjunction with the ability to reduce the lines in mm.

I've only done tests on laser (and not of that many varying numbers) but so far I'm getting nothing but A's... the test on the digital press will be done within the hour. I'll let you know how that goes.

I also need to understand exactly what the code does... I've looked through it and get the basic ideas but if it's ok I would like to post some more specific questions - I might have to do the same to an EAN 13 or a 2 of 5 next time (plus I dont like using code I do not understand).

Once again many thanks... you've really helped me out (and ensured a sale for Objectif Lune)

Danny