WDC Investigates: Printing – Print Quality Problems
Metamerism and Bronzing
Two of the most noticeable quality imperfections that relate to inkjet printers are metamerism and bronzing. Metamerism is where the neutrality of tones, especially grey tones, is affected markedly when the lighting used to view the print is altered. This is most characteristic with printers using pigmented inks when printing b&w images. Just by moving the print from one room to another you can see that the warmth of the tones changes; sometimes it can seem the print has a faint magenta or blue tint. Improvements in inks have steadily eroded this problem, but I still see it at galleries and exhibitions. Maintaining accurate calibration of the printer through colour-management profiling can help.
Bronzing is specifically concerned with glossy and semi-glossy papers. Again, it’s mainly a manifestation of pigment ink printers. When the ink dries on the shiny surface of the paper, it can create optically refractive layers that result in a reddish gold variation in the surface shine when viewed under bright light from various angles. Improved ink layering has reduced this problem considerably, but if you can’t get good results on gloss paper, use matt surface paper instead.
Tips For Running Smoothly
Pointers to help you to do your prints justice
Don’t make a critical evaluation of the colour in an inkjet print until the ink has fully dried and the colour has stabilised. This can take up to 24 hours depending on the type of ink and paper used.
If your printer uses pigmented inks, then when installing a new ink cartridge, give it a gentle shake for a few seconds to ensure that there is no settling of the pigment particles.
Don’t try to squeeze out that extra millilitre of ink from an ink cartridge by running excessively past the low ink warning. Some printers with permanent print heads can be rendered inoperable if air gets into the print head.
Always double check that the printer driver or on-printer setting, if using a stand-alone printer, is set correctly for a specific brand and type of paper. Two photo papers of identical appearance from different manufacturers may deliver very different results despite maintaining identical printer settings.
If your printer supports both ‘photo black’ and ‘matt black’ ink cartridges, be aware that each time the printer switches between them, ink wastage occurs while the ink channels and nozzles are flushed. Matt black ink is required when printing onto fine art papers that invariably have a matt surface finish.
Periodically, print a nozzle-test print to ensure that you won’t waste a valuable sheet of photo paper through clogged nozzles and banding.
When switching off your printer, use your printer’s on/off button. It may seem obvious, but sometimes it may seem more convenient to use the mains wall socket power switch. But this prevents the printer from parking the head correctly, and so sealing the head nozzles so that they don’t dry out when left exposed for long periods.