Though I have taken photographs my entire life I am embarrassed by my scant knowledge of photography. When I was young I took photos of my friends. Later I took travel pictures. Now most of my photographs are reference shots for paintings. After I started painting I realized that I also needed photographs of my work. At first this was just to keep a record of everything I had painted because, as previously discussed, I regularly discard the older unsuccessful ones. I look at these periodically to remind myself of where I started. Now I need photos for my website and to enter juried events. After a few years of frustration and many failed attempts to understand technical discussions online I came across a very straightforward "how to" article that completely changed my approach and results. Rather than parroting the process here I recommend that you click on How To Take Great Photos Of Your Artwork in the right hand column under favorite blog posts/articles and start reading.
I now own a very good Canon digital camera and I set it on "automatic everything" including white balance. I use ISO 200. I rarely do anything other than cropping the photo once I have downloaded it.
The equipment needed for lighting can be bought inexpensively on Amazon. At the time of this writing this kit by Emart is available on Amazon Prime and costs just under $60. It does not come with assembly instructions but I was able to figure it out so it can't be that difficult.
Here it is in my studio-
Important features- the white umbrellas diffuse the light of the natural light fluorescent bulbs which come with the set up. This eliminates both glare and excessively warm or cool light. The camera is on a tripod to avoid movement and is not extremely close to the painting. It is better to zoom in. Set the camera on the highest possible photo quality. Don't use the flash. Take the painting out of the frame if it is in one.
I had heard of all kinds of ways to get natural light, such as photographing outside in the shade. I never found a way to eliminate glare until I used this set up.
So you can see the difference I have included 2 photos of the same painting. The first was taken with natural light coming in the window of my studio, a north exposure which should be good. I held the camera in my hands and got close to the painting. The second is with the set up shown above. Click on each photo to get a better look.
Actually I got kind of lucky with the first one this time, but if you look closely you can see a fair amount of glare on the left side of the painting and also a bit in the distant mountain. But also notice that the rock formation on the right is almost completely dark. You can't see the half tones that are visible when the panel is evenly lit. I did not have the ceiling lights on when I took the first photo but if I had there would have been a lot more glare though the lighting would have been better on the right.
I hope this was helpful. Be sure to read the article I referenced above for a more detailed explanation.
Thanks for reading!