Tim Grey Guest Post – Ripples in Inkjet Prints
From time to time, we re-post an article from the Ask Tim Grey Archive. Tim is a top educator in digital photography and imaging. We encourage you to sign up for his Ask Tim Grey email newsletter, and seek him out should he be teaching in your part of the world.
Today’s Question: I am primarily a nature photographer and have been using a luster paper 240 gsm. My images look good but many, once framed seem to have a ripple effect. (Yes, they are mounted properly.) I have been told that two things can contribute to that problem, the weight of the paper and the use of luster. A professional photographer friend suggested that I should consider switching to Baryta Gloss papers that have a GSM of 310. Do you have any advice?
Tim’s Answer: I’m not sure that I would really agree that paper thickness or the use of Luster paper in particular (or even semi-gloss papers in general) are the key issue here.
First, the GSM rating stands for grams per square meter, and is a standard measure of the weight of a paper. Generally speaking you can think of GSM as being a measure of thickness, since a thicker paper will obviously (at least generally) weigh more than a thin paper. However, it is really more a measure of density. Different paper materials have different densities (and thus different weights). In other words, just because a paper is heavy doesn’t mean it is especially thick, and just because a paper is thick doesn’t mean it is heavy.
It is true that thinner papers will tend to ripple more readily than thick papers. For example, if you print a photo to a sheet of standard copy paper, you’ll likely see significant rippling in the final print. On a thick paper this is less likely, because the paper is better able to absorb the ink. However, above a certain weight, especially with papers specifically designed for printing photos, there really isn’t a benefit to even greater weight or thickness. Mostly you would choose a thicker paper because it feels more substantially when handled by a customer, not because of printing issues.
Whether or not the paper is coated is also a factor. But if anything, the Luster paper is providing a bit of an advantage here, because it is keeping the inks more on the surface, reducing ink spreading. An uncoated paper would certainly absorb ink better, and with a high-quality paper of adequate thickness this can help reduce the risk of rippling. But that’s actually getting to the point of one of the key causes of rippling in a print: Too much ink.
Depending on the printer you are using, it is possible to reduce the amount of ink that reaches the paper. This is often available in an “ink control” setting, but it will vary based on printer make and model. You can also print at a lower quality setting (sometimes referred to as a resolution setting) to reduce ink usage.
The other key factor is how the print is mounted. You don’t mention how your prints have been mounted, but in my opinion the best way to mount in order to reduce rippling is to use a cold-mounting process where the entire back of the image has an adhesive applied, and then pressed onto a mounting board, matted, and framed.
Using an uncoated matte paper can indeed help reduce the appearance of rippling, because they are better able to absorb the inks. But my feeling is that you should choose a paper based on aesthetics, not based on rippling behavior (though a paper that ripples considerably obviously might need to be avoided regardless of how nice the paper is otherwise). Because tastes vary, I highly recommend obtaining a sample pack of a variety of papers (both from your printer manufacturer and third-party paper manufacturers) and conduct some testing to see which papers you like best, and which among those don’t ripple.
You might also consider a process to accelerate out-gassing of your prints. I don’t know that there is a solid scientific basis for a contribution to rippling here, but my anecdotal experience has been that using a process to accelerate out-gassing helps reduce the incidence of rippling. It could be my imagination, but this process is a good step to help avoid fogging of the glass for framed prints, so worth doing in any event. The process is simple: After printing and allowing the print to dry, place sheets of plain paper over the print and allow to sit for about 24 hours. If the paper wrinkles significantly you might repeat for another 24 hours with fresh sheets of paper.
Between adjusting the amount of ink that meets the paper and making sure the prints are mounted in the best way, you should be able to avoid ripples in your framed prints.