Comparison of Technologies: Ink versus Laser
von Florian Heise
übersetzt von Ulrich Junker
Erschienen am 24. August 2009 bei Druckerchannel.de, 17 Seite(n)
Our lab uses several test documents to judge the quality of a print:
- Quality of photo print: DC_Fotoyield and Fuji test picture
- Quality of graphics print: DC_Grafiktest
- Quality of text print: DC_Business-Brief
- Bleeding-/registration test: DC_bleedtest
DC shows clippings of the yellow-blue parrot, of the small eye in the middle of our test document DC_Fotoyield, and of the two ladies in our Fuji test picture.
The lab examines colors, contrast, and image sharpness. All print-outs are scanned with a professional photo scanner.
HP´s Officejet Pro 8000 prints with ink instead of toner powder. Print quality with four inks is distinctly better than with black toner only. The monolaser printout is rather dark, and a lot of raster mars the picture. Inside the circle you see an enlarged part of the parrots pupil.
The lab compares the results of a monolaser printout with HP´s print in black-and-white mode, "High quality". Grayscales are generated with all four colors, plainly visible in the enlarged part of the parrots pupil. Resolution is excellent, with a slight tint.
Genuine black-and-white pictures can be printed by setting the printer driver to "Black ink only". This results in pictures without tint, but resolution is lower.
The enlarged part of the pupil illustrates clearly the two differing technologies. The monolaser uses a 45 degree raster and clearly visible raster points. On the right side you see the ink printer´s results. The upper half greyscale print with four colors, the lower half with black only.
To test photo quality the lab scans a tiny clipping of the test document with 1.250 dpi. In this magnification the monolaser´s raster point are clearly visible, ever with the naked eye. The ink printer´s color pixels can only be detected in this enlarged part of the photo. To the naked eye they are invisible.
A photo print with Brother´s monolaser is almost unusable. There are vertical stripes and a definite raster. HP´s ink printer shows no raster in it´s greyscale photo (Driver "High quality"), but some tint is in it.
DC shows clippings of the corona, the grey area, and the minute 2-point font, all on our test document dc_grafiktest.
- Corona: This test reveals, whether or not the printers can depict fine lines correctly and without moiré effect.
- Grey area: Color printers should depict grey areas homogeneous and without annoying tint.
- 2-point font: This test shows, if a color printer can reproduce finest details.
Brother´s laser fails to convert the color segments into different grey scales. And there are moiré effects. This is much better with HP´s printer: Color segments are correctly transformed into different shades of grey, fine lines are printed with high resolution. And there are no moiré effects, which are common for raster printing.
The quality of printing grey areas is very important, since bar or pie charts are often filled with different colors, which have to be converted into grey scales correctly. Although Brother´s monolaser prints with a coarse raster, the grey area is printed without annoying vertical and horizontal lines. The picture appears somewhat blotchy, however.
The grey in the HP´s printout is homogenous, with high resolution, and without bothersome lines. But you find a slight tint.
If you need minute fonts on circuit diagrams or blueprints, your printer should be capable of displaying them. The word “Druckerchannel” below is printed in 2 point (0,5 millimeters font height). HP´s printout is well readable, Brother´s somewhat blurred.
With ink printers adjoining colors sometimes blend into each other (bleeding). This phenomenon you might remember using your fountain pen on blotting paper. HP´s officejet puts pigmented inks on the paper, so colors do not blend. Brother´s monolaser uses toner powder, bleeding cannot occur. The vertical color lines have a coarse raster, however.
Both printers give out text in excellent deep black. The enlargements show some toner fog (Brother) and satellite droplets (HP), which are barely visible to the naked eye.