HP Designjet T790 1118 mm User Manual

4.Select the percentage of change from –100% to +100%. To correct light banding, decrease the
percentage.
To correct dark banding, increase the percentage.
5.Press OK on the front panel, to save the value.
6.Wait until the front panel displays the status screen and reprint your print.
Return to default calibration
Returning to the default calibration sets all the corrections made by the paper advance calibration to
zero. To return to the default paper advance calibration value, you must reset the...

17 Troubleshooting print-quality issues
●General advice
●
Print quality troubleshooting wizard
●
Horizontal lines across the image (banding)
●
Lines are too thick, too thin or missing
●
Lines appear stepped or jagged
●
Lines print double or in the wrong colors
●
Lines are discontinuous
●
Lines are blurred
●
Line lengths are inaccurate
●
The whole image is blurry or grainy
●
The paper is not flat
●
The print is scuffed or scratched
●
Ink marks on the paper
●
Black ink comes off when you touch the print
●...

●The Image Diagnostics Print
●
If you still have a problem
ENWW165
 

General advice
When you have any print-quality problem:
●To achieve the best performance from your printer, use only genuine manufacturers supplies and
accessories, whose reliability and performance have been thoroughly tested to give trouble-free
performance and best-quality prints. For details of recommended papers, see 
Order paper
on page 142.
●Make sure that the paper type selected in the front panel is the same as the paper type loaded
into the printer (see 
View information about the paper on page...

Alternatively, or if you have other print quality problems, you can continue reading this chapter.
Horizontal lines across the image (banding)
If your printed image suffers from added horizontal lines as shown (the color may vary):
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Check that you are using appropriate print-quality settings for your purposes (see 
Printing
on page...

Lines are too thick, too thin or missing
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Check that you are using appropriate print-quality settings for your purposes (see 
Printing
on page 52). Select the custom print-quality options in the driver dialog, and try turning on the
Maximum detail option (if available). You may wish to reprint your job at this point in case the...

1.The problem may be inherent in the image. Try to improve the image with the application you are
using to edit it.
2.Check that you are using appropriate print-quality settings. See 
Printing on page 52.
3.Select the custom print-quality options in the driver dialog, and turn on the Maximum detail
option (if available).
Lines print double or in the wrong colors
This problem can have various visible symptoms:
●Colored lines are printed double, in different colors.
●The borders of colored blocks are...

1.Check that you are using appropriate print-quality settings. See Printing on page 52.
2.Reseat the printheads by removing them and then reinserting them. See 
Remove a printhead
on page 129 and Insert a printhead on page 132.
3.Align the printheads. See 
Align the printheads on page 186.
Lines are blurred
Humidity can cause ink to soak into the paper, making the lines blurred and fuzzy. Try the following:
1.Check that your environmental conditions (temperature, humidity) are suitable for high-quality...

Line lengths are inaccurate
If you have measured your printed lines and find that the lengths are not sufficiently accurate for your
purposes, you can try to improve line length accuracy in the following ways.
1.Print on HP Matte Film, for which your printers line length accuracy is specified. See 
Functional
specifications on page 206.
Polyester film is about ten times more dimensionally stable than paper. However, using film that is
thinner or thicker than HP Matte Film will reduce line length...

The paper is not flat
If the paper does not lie flat when it comes out of the printer, but has shallow waves in it, you are likely
to see defects in the printed image, such as vertical stripes. This can happen when you use thin paper
that becomes saturated with ink.
1.Check that the paper type you have loaded corresponds to the paper type selected in the front
panel and in your software. See 
View information about the paper on page 46.
2.Try changing to a thicker paper type, such as HP Heavyweight...