Why does my old HP 6L print images better than my newer HP laserjets?

[PeterBJ]

......Just the image itself is about 15cm tall, and I print at 94%.

I have downloaded a thumbnail instead of the image, The image prints at 15 cm x 15 cm or 6" x 6". My prints then look like those printed by The Hat, Here is a 75 dpi scan of 3 prints joined, click to enlarge:



I have made 1200 dpi scans of the small red rectangles, this clearly shows the difference between the 3 printers. Notice the two HP printers have a very newspaper image like print and the Canon inkjet has a much smoother image. Top is HP DJ930, middle is HP LJ1018 and bottom is Canon MP 980. Click to enlarge:









It seems that number of dpi alone doesn't tell all about print quality. How the printer processes the image file seems just as important.

 

[The Hat]

Just the image itself is about 15cm tall, and I print at 94%.

My first prints turned out at 11 cm wide and I used Windows photo Viewer to print them..
This time i used PhotoShop and the prints were 15 mm wide, and
the prints look completely different.


click to enlarge..
At first I didn’t notice the print was of a ginkgo leaf, but on checking the print is a good rendition.


My Ginkgo is just coming into leaf, it’s always the last tree to bloom..

 

[PeterBJ]

I have also been confused by the Ginkgo Test image. Copying and printing it from post #6 produces a 20mm x 20mm print, but opening the image in a new tab and copying it produces a 15 cm x 15 cm print, so the image in post #6 is a thumbnail I think.

A 300 dpi scan of the thumbnail print made by the HP Laserjet 1018 looks very similar to the right hand print of post #1:

 

[smeelah]

I'm sorry - there was a typo on my part. For me, the image alone is 1.5cm in height and I print it at 94%. I am surprised that it is printing so large for you. Sorry to use up so much toner!

And that is also why I am surprised that I can't get the image to print without dots or lines on my other hp laserjets - just the 6L.

 

[The Hat]

Sorry to use up so much toner!

And that is also why I am surprised that I can't get the image to print without dots or lines on my other hp laserjets - just the 6L.

Don’t be to worried about our toner usage…

One of the ways you can try is to enlarge your image in your App. then print the image at the correct output size, that will reduce the lines and dots that your experiencing.

I saved the Ginkgo test Jpeg as a PDF and then printed it on the laser again, it came out at 75 mm wide with much better quality ..

 

[smeelah]

Don’t be to worried about our toner usage…

One of the ways you can try is to enlarge your image in your App. then print the image at the correct output size, that will reduce the lines and dots that your experiencing.

I saved the Ginkgo test Jpeg as a PDF and then printed it on the laser again, it came out at 75 mm wide with much better quality ..
View attachment 14230

Thank you.
I did increase the image to 2000dpi, keeping the same print size / canvas size. I also tried printing as a pdf, and in another app. The print remained dotty.

The result of your print looks great!

So you think that the issue is somewhere in my settings and not the capability of the printer? With the HP 1018, I have to use an HP 1022 laserjet driver since I am on a Mac. I finally decided that must be the issue and got the HP M28 laserjet and had the same issue.

 

[The Hat]

I did increase the image to 2000dpi, keeping the same print size / canvas size. I also tried printing as a pdf, and in another app. The print remained dotty.

No your problem is I reckon, that you don’t quite understand how PPI and DPI work.

Your increasing the DPI in your print instead of leaving it at your normal 600 DPI, the answer is to enlarging the image itself twice or three times its size and then reduce it in the print driver back to its normal size, that’s the size you wish the print to finish at..

Instead of printing it to PDF, try saving it to a PDF file and then print the PDF from ACRO Reader..

P.S. the last test print above was done on the same laser printer as the previous ones were and at 300 DPI..

 

[smeelah]

No your problem is I reckon, that you don’t quite understand how PPI and DPI work.

Your increasing the DPI in your print instead of leaving it at your normal 600 DPI, the answer is to enlarging the image itself twice or three times its size and then reduce it in the print driver back to its normal size, that’s the size you wish the print to finish at..

Instead of printing it to PDF, try saving it to a PDF file and then print the PDF from ACRO Reader..

P.S. the last test print above was done on the same laser printer as the previous ones were and at 300 DPI..

Yes, I would typically leave the document print size at 8.5" x 11" etc. but increase the resolution.

This time I kept the dpi of the full document to 300 with the page size at 25.5" x 33" but printed 'to fit' a 8.5" x 11". The print resolution showed as 943 ppi. I also tried 600 dpi with the page size at 34" x 44".

It didn't improve the print quality in any significant way - I can still see lines and dots - but is this what you meant for me to try?

 

[The Hat]

It didn't improve the print quality in any significant way - I can still see lines and dots - but is this what you meant for me to try?

That’s exactly what I wanted you to try, because you’ve seen the results that I got in my last test image when I did exactly the same thing to your original JPEG, your results should change dramatically and not stay the same.

With inkjet printers the output results are calculated in PPI but in laser printers its measured in DPI, the only thing that maybe be wrong is the laser printer your currently using, have you tried saving the image as a PDF file first then printing it from AcroReader..

 

[smeelah]

I was hoping it was a setting since I am getting that result on two different printers. The 6L and 1200 laserjets printed smooth with regular size images and the 1018 and M28w print with the dots and lines showing.

I tried pdfs with photoshop (cs5), preview and acrobat reader. Very similar.

Since they are macro images, I could probably get away with lines and dots if the outlines would print smooth and not jagged.

I really appreciate your help!