Image Quality in VFP6 Report

[CFace]

Hi All,

I ran into a problem using a barcode font in a report in VFP6. Client needs the Code39 (3 of 9) barcode to be rotated 90 degrees CC from a normal horizontal position.

Since the VFP 6 report writer doesn't offer built-in functionality to rotate specific objects, I resorted to creating image files for the barcodes I needed. I made them to "spec" in Fireworks, rotated as needed, exported out as highquality jpgs. They are free of non-black and non-white pixels (i.e. no noise). By themselves, they look great.

However, it seems the way they're rendered on the printed output page is of lower quality and the machine that scans them can not do so correctly on a consistent basis.

Does anyone know how to improve the printed output quality? Should I change from jpg to another format? Does it depend on the printer driver I'm using? etc.?

Thanks in advance,

Stewart

 

[JRB-Bldr]

Since this is question is about print-out quality and print resolution, this is not really a VFP issue, but here is a suggestion anyway.

I would first try printing the images to the specific printer outside of VFP.

I would do this in order to determine the best printer configuration and best image file format that can be generated. Try different image formats (jpg, gif, bmp, etc.) and try different printer settings if available (draft mode, best mode, max dpi mode, etc.).

An additional test you might make is to test the dpi for the images themselves. In the image printer that my clients use we can set the bpi for the images (200x200 or 300x300, etc.)

Lastly barcodes have a width ratio which can be modified to improve the readability by certain less-effective barcode readers. Making both the space width and bar width equally wider can sometimes improve the over-all readability.

Once you discover the optimum settings that will generate reliably readable barcodes you can then use those settings when you go back to your VFP application utilization of the images.

Good Luck,
JRB-Bldr

 

[Mike Lewis]

Stewart,

Are you saying that the images look OK on the screen, but the quality drops when you print them?

If so, that suggests that the printer doesn't have a high enough resolution. Can you find an alternative, better-quality, printer to test them with?

Mike


__________________________________
Mike Lewis (Edinburgh, Scotland)

My Visual FoxPro site: www.ml-consult.co.uk

 

[CFace]

Hi JRB & Mike,

Thanks both for replies.

I will double-check printing outside of VFP. I will try bumping up the dpi in the image itself and try some other formats (hence why I asked about other changing from jpg).

In this application, client is a mail-shop with pre-sort machine capability. They use equipment on the level of that found in US Post Offices and utilize high-speed processing for high-volume counts.

The operator explained to me that he sets the camera to read the first barcode (on the top sheet in a batch) like a calibration process. He then expects that all subsequent pages would have a barcode of similar quality.

A few pages into the batch and we're experiencing a bad read. He can re-adjust the camera and get a good read on the barcode, but its quality differed from the previous he used to set the calibration for the batch/run, so it was rejected.

When we look at the code under a magnifying glass, it doesn't appear to have the same quality. It's almost like there is a slight pixelization outside of the bar perhaps in a grey-ish color slightly less than true black (like the effect of anti-aliasing in a graphics software pkg).

My image (in my graphics software) shows NO pixels there as I ensured they were clean. I even read back in the jpg I made to ensure it had no extra pixels. It was clean.

So, my thoughts were that the printer rendered them slighly differently than they were on screen.

The printer is an industrial-use Heidelburg Digimaster 9110. This is a high-quality, high-volume, high-speed machine for use in large print shops or mail shops.

>> Are you saying that the images look OK on the screen,
>> but the quality drops when you print them?

Yes. The printer has sufficient quality to gen the images (see above).

Regards,

Stewart

 

[Mike Lewis]

Stewart,

Sorry we haven't been able to give you any more definite help. I hope you manage to solve it.

If you get any further information that might be relevant, let us know.

Mike


__________________________________
Mike Lewis (Edinburgh, Scotland)

My Visual FoxPro site: www.ml-consult.co.uk

 

[JRB-Bldr]

Let us know the results of your testing.

Obviously the resolution that you can see by viewing barcodes on-screen is nowhere near the same resolution that can be 'seen' by a barcode reader - especially a good one.

I think that if you get the images themselves into the highest practical bpi and into the best file format, then you will most likely resolve your problem.

Good Luck,
JRB-Bldr