Troubleshoot the image print transform

The following are answers to questions that might arise when you use the image print transform function or the Convert Image API:

• Why does it take longer to process PostScript data streams?

  One reason why PostScript data streams take a long time to process is the amount of information that needs to be transformed. Color documents especially require large amounts of memory and many data conversions, which means longer processing times.

  Note:
  If the photometricity of the converted data stream is not requested, it is assumed by default to be RGB, or color. However, if you know you do not want RGB, or the input data stream is not color, specify an image configuration object that only supports black and white output. This will greatly increase the throughput of the image print transform function, and speed up PostScript processing.
• Why is the converted data stream positioned incorrectly on or off the page? Why is it not centered?

  The resolution specified in the image configuration object is probably not supported by the printer that the object is configured with. When this happens, an incorrect no print border is retrieved from the image configuration object and the data is consequently positioned incorrectly on the output page. The printer might also be set up to automatically add a no-print border, which will cause the output generated by the image print transform function to be shifted on the page. Verify that the correct image configuration object is being used with the printer, that the printer has been set up properly, and that the printer and has been physically calibrated.

• Why didn't the PostScript data stream generate a new data stream?

  The PostScript data stream probably did not contain any printable data. To verify this, start the image print transform function and check the job log of the writer. Look for a message that indicates that no printable data was found. If no message exists, an error might have occurred while processing the file. Refer to the job log of the corresponding QIMGSERV job.

• Why is the printed image three times the original size when converted from color or gray scale to black and white?

  When a color image or gray scale image is converted to black and white, a dithering process takes place. In this process, a single color or gray scale pixel is transformed into a 3x3 matrix of pixels. Each pixel within this matrix will be either black or white, depending on the color being rendered.