How to isolate an image on white

Several people have said that my photos look great and they would like to learn the technique. So I decided to write a series of posts which will reveal my “secrets”. I have already written a post named How to take good macro photos which I recommend to read also because it covers some of the basic requirements of macro photography which are important to master because you need to shoot right to get a good result.

I often isolate photographed objects (mostly rock samples) on white. I do it because it looks nice and professional if people see only the things I want to show them. There are really many ways to accomplish that and I am not saying that my method is the best but it works for me. The most professional way to do it is to arrange a special studio with powerful scattered lighting and white backgrounds all around the photographed object. If you do it this way, you could take photos isolated on white with your camera and need almost no photoshopping later. However, this is not my approach because I often find myself in very uncomfortable conditions. Sometimes in the field, sometimes in a dimly lighted museum warehouse with very little room, etc.

If I want to isolate photos on white later, then I take care to organize white background behind the object in the first place. Easiest way to do it is to place a white sheet of paper (A4 format is large enough in most cases) behind the object. It serves two very important purposes. I want to cut out the object later and if the background is already white, I can do it relatively easily in Photoshop without leaving ugly colored rims to the object. If my background is gray for example, then I have lots of trouble later because I need to manually go over the entire outline of the isolated object to isolate it properly which wastes lots of time. I am not even talking about red or blue backgrounds which is a nightmare.

Another reason for using white background is to get the correct white balance. It is difficult to judge whether your photos have right colors without a reference surface. White background is good for that because I know that it has to be white on my photos and if it is bluish or reddish instead, then I can do something about it. This is also very easy to correct in Photoshop. The issue of white balance is of great importance in photography and definitely deserves an entire post dedicated to it (maybe I will write about it some other day). The method I described above may not be the best or most professional but you can be sure that if you have something in your photo that you are sure has to be white, then you are in a good position to get the colors correct.

Now we have a photo of a rock sample and a white piece of paper behind it. Now what? First of all, I hope you read the other article I mentioned before. There I listed several key points like the necessity to use tripod and additional light sources if you take the photos indoors. Underexposed photos with no focus are not worth our time. Isolating on white will not make them any better. It is necessary to stress these points because these are the most common mistakes beginners do: they do not have enough light and their camera shakes while they are photographing.

I will leave most of the tricks for my next article: How to quickly enhance your pictures. Here I just cover the method I use to remove the background. In reality this is one of the last things I do after correcting white balance and other important steps. I will open the photo in Photoshop and select the Magic Wand Tool (hotkey: W). I use it to wipe over the background to outline the sample. Photoshop understands it easily if there is enough contrast between the background and the object. However, it almost never makes a perfect job. You have to zoom in and go over the entire outline of the object and make necessary adjustments where needed. To do that press Alt (these guidelines are for Windows users, Mac commands are similar but different keys are used) and wipe over the object to enlarge the selection or Shift to subtract from it. Note that we are really selecting or outlining the object now, not the background.

But in many cases Photoshop can not properly understand you and you have to take a full control of the process. To do that select Lasso Tool (L) and just draw a line around the object as closely as possible. You have to zoom in to do it. Here again you should press and hold down the Alt key if you wish to add and Shift key if you wish to subtract. It may seem complicated at first but experiment a little and quite soon you feel comfortable doing it. After you have correctly outlined the object, you need to inverse the selection because we want to remove the background, not the object we are working on. To do that, choose Select -> Inverse. Now we have the background selected. To remove it, just click Edit -> Fill and choose white color and take care that the opacity is set to 100% and press OK. It means that we do not actually remove the background. We just paint it white but this is exactly what we need at the moment. You can also choose black background. Sometimes it works well with light-colored objects.

It was as simple as that. There are other methods to do the same but for me it seems to be the easiest one. In the next article I will show you some easy tricks which will make your photos clearer and reveal their real beautiful colors.

4 comments to How to isolate an image on white

  • Hollis

    neat! thanks for the idea and tips.

  • Toastar

    Protip: Learn to love quickmask(q). Select a hard edged brush, Hit default colors(d), and you can flip back and forth quickly with x if you make a mistake.

  • Howard

    I second Toastar’s quickmask tip. It’s much easier to paint than to lasso. Also, here’s another tip: open your original photo, Select All –> Copy –> New (Preset “Clipboard”; set background contents to “transparent”) –> create a new layer (so you have 2 layers; activate the upper layer) –> Paste. Now your original image is in the upper layer of the new document. Do your lassoing & quickmasking, then invert selection and delete what you don’t want. Now you can fill the bottom layer with whatever color you want: white, black, grey, etc. The advantage is that it’s quick and easy to change the background color if you decide you want to change it, without having to go through all the lassoing/quickmasking a second time. Also, any tweaking you do to the image (contrast, levels, color correction, saturation, sharpening, etc.) only affects the image layer, and your background color stays the same.

  • Thanks for the tips. Yes, I know that working with layers has its advantages. I am more experienced to work with Adobe Illustrator where layers are absolutely crucial. So far for some reason I have managed to live without them while photoshopping. Perhaps I’ve been too lazy for that or have managed to do my simple operations without them.

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