If you’ve been doing this for a while, you probably have your own way of getting a good photograph of your artwork. I’ll tell you what I do.
To me it is important to photograph my painting in natural light only. I have a bedroom that has two nice windows. I turn off any lights and place the painting flat on the bed, hoping to avoid any light coming in from the sides. I use my Nikon SLR and do my best to hover over it so the picture is square and not skewed. The hardest part is not casting a shadow. I take a few pictures and then open them in PhotoShop.
Open PhotoShop. You are greeted with a page with a large “New…” button and a large “Open…” button. Click on the Open button and navigate to where you have your photographed picture. If you don’t have this screen, then go to the top menu and click “File.” You’ll find “New” and “Open” here, too.
When you locate your picture, click on it and then “open” at the bottom of the little screen.
And then the picture opens in PhotoShop.
Whether I have scanned a picture or taken a picture of it, I find that the blacks are washed out and the picture needs a slight value adjustment. In this case, the brightness and contrast are way off.
You can see a grid because the first thing I do is crop it with the crop tool on the left, 3rd one down on the left of the tool palette. After you have determined how you want it cropped, move your cursor to the top left icon, the “Move” tool, and click on it. You’ll see a little menu pop up that says “crop?” and “don’t crop.” Click accordingly.