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Isolation quality control. How to check if the background is truly white?

Typical mistakes

The product to the left was damaged when it was isolated. The Quick Selection tool did it

Now let’s talk about typical isolation flaws. The process of background removal is tricky and has to be done with deep understanding of Photoshop tools and commands. Otherwise, it might lead to mistakes that affect the images in a bad way. The main idea of isolation is separation. The item gets separated from the background and this where it gets complicated. The edge of isolation, which usually the same as the product’s edge, should look nice and natural. Some tools and techniques tend to leave ugly edges by feathering too much, or, the opposite, making them too hard. There are many ways how to ruin an edge. You can use inappropriate tools. Use the Polygonal Lasso to isolate round surfaces, or use a soft Eraser brush to isolate fur – you’ll get a weird edge. Use multiple tools with different settings and you’ll get yourself into an even worse situation.

The image on the left is not isolated properly because the fur looks too soft and it's partially erased

Sometimes it’s not just the edges, you can also damage products while isolating them. Use the Magic Wand with a wrong Tolerance setting or use the Quick Selection tool and you might accidentally fill parts of the objects with white. And parts of the background might still remain there. Also, remember, we’re talking about product image retouching. It means that there are a lot of images with the same requirements. If you isolate one with a blurry edge and another one with a hard edge, you ruin them both. Consistency is important, too.

And even if everything went well, you can still ruin your images by choosing the wrong interpolation mechanism to resize your image. Like the one that is called “The nearest neighbor” and is supposed to preserve hard edges. And hard edges you get. That's why when I do isolation, I use the isolating action all the time, as it gives me a consistent edge. And if an edge has to be soft, like where the shadow blends in the background, or if an item is furry, I only use a 0% Hardness brush. If I need to erase something on an object while it's still high-res, and the edge has to be smooth enough, I use a 75% Hardness brush. It's also important to make sure that you're not feathering any selections by default, so check the selection making tools, especially the Pen Tool. If you feather a selection and run the isolating action, the edges will become too blurry.

Final isolation check

Working as the head of the retouch in one of the biggest online stores in Russia, I often dealt with images sent by suppliers, which were supposed to be uploaded on the website. There are some brands that prefer that their own imagery is used on all the websites that sell their products. In general, using suppliers’ images is quite common in e-commerce, especially if it's about perfume or cosmetics. After some realigning, resizing and making sure they are up to the standards of the store, of course.

Those images were usually all different and supposedly made by random retouchers in random time by random standards. The objects in these images were often isolated on a white background, as it’s a very popular approach. But most of the time the isolation was not perfect, so I’ve had to check the images for isolation flaws before uploading them. In fact, checking for isolation flaws is actually one of the retouchers’ responsibilities, but as I could see, it was widely ignored. So widely, in fact, that encountering a perfectly isolated image was a rare event.

By perfectly isolated I mean an image with a totally white background with no spots or dots of darker color, where the product has smooth edges and nice soft shadows (if there are any shadows, of course), and where the product is not damaged in terms of color and tone and its parts are not eaten away by any of the isolation tools. But for now, let’s just discuss the background issues.

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There’s an easy way to check if the isolation is good in Adobe Camera Raw. Open all your isolated images at once in the plugin and switch the Highlight clipping warning on. You can do it manually by clicking on the inverted triangle in the upper right corner of the histogram or just press O. Now everything that is white will turn red. By white I mean the areas filled with 255-255-255 in every channel of RGB. If the background looks white to you but has some other values, like 254-254-254, it’s not white, it’s gray. You might not notice a difference that slight, but here in product image retouching we don’t judge the images by their looks. Numbers are more important. Among the images I've opened, there's an image that is not isolated properly. Instead of white, the background is filled with light gray color, which is 254-254-254. Thanks to the highlights clipping warning switched on, I can easily distinguish the faulty image.

Can you see the rectangle?

On my monitor, it might look white, as well as on your monitors. But in fact, there’s a rectangle here filled with color that is not white, and its existence ruins the isolation. It’s easy to find it if you know how to check, and some people will be able to see it on their monitors, too. So there’s no way we can say: alright, this is just a harmless rectangle, the background looks white enough. No. During the process of isolation, if everything goes well, the existence of areas, spots or dots of weird color is not tolerable. It means something has gone wrong. And if it has, it must be corrected before the image is seen by anybody else.

There’s only one color in Photoshop that is called white. It has 255-255-255 RGB values. Anything else is gray. Well, gray is a color, too, and in some cases, some images are isolated on gray instead of white. But it doesn’t matter: whatever color you choose, isolation should be perfect. It doesn’t matter if you can see it on your monitor or not, because other people will. So as you retouch images, it’s a good idea to check if the isolation is done well or not. There are multiple ways of doing it. First one, as I already showed, is ACR highlight clipping. You can also use the Levels or Curves to check if the isolation is fine or not. Just access the Levels and drag the leftmost slider as far to the right as possible. By pressing Enter I can apply this change to the image, and if I want to do it once more, I don’t have to access Levels and move the slider again, I can just press Ctrl-Alt-L and see the last change applied immediately. And then just press Escape because I don’t need to apply this to the image.

And there’s another way to check if isolation is okay, especially good in revealing the small dots which are hard to notice otherwise. It’s trimming. Let’s see how it works. So this is our object in need of isolation. And the job is done, but there are some black dots there, I’ll draw them with a brush. They are really really small and you can’t see them, especially when the image is zoomed out, and its scale is less than 100%. And when we check this image with the Levels or ACR you can’t really find these dots. But they are there, we know it. So what I do is just Trim the image with the Trim command. It takes the color of the top-left pixel, which is white, and it trims away everything that is white until it encounters something that is not white. Like the dots. If the background was perfectly white, it would trim everything except the object. But it did not, and it means that something that is not white is there. And when you know it you can search for it and remove it from the image.


There's another way how to integrate the isolation check in the retouching process. Whenever you isolate an image, you run the isolating action, and right after that, you run the isolation checking script. What it does is make the image fit the screen, adjust the Levels so that you can see if your isolation is fine or not, wait for 300 milliseconds and then just undo the Levels step so that you don't have to do it manually. If 300 milliseconds is too long or too short a time for you to check, you can change it to another value that you find appropriate. If you insert the following code in the ExtendScript ToolKit and run it when an isolated image is opened in Photoshop, you'll see how it works.

#target photoshop
var doc = app.activeDocument;
runMenuItem(app.charIDToTypeID("FtOn")); //fit on screen
doc.activeHistoryState = doc.historyStates[doc.historyStates.length-2];

So if you do it right after isolating an image by running this script at the end of the isolating action, you'll be able to immediately see if the isolation is okay or not. As you can see, checking for isolation flaws is not that hard, but it’s tedious and can be time-consuming. So if you check your own images, your best bet is to isolate them well in the first place. And if you check others’ images, you might as well teach them how to check for isolation flaws so they do it themselves.

If you still think this is not necessary because most people will not even see these flaws, well, think twice. Isolation flaws can be really noticeable sometimes, so you might encounter problems when the images make their way onto the website. Because whoever sees them will realize that something went wrong with the retouching. As professionals, we should never be tolerant of this kind of things.

There's a separate chapter dedicated to quality control, and we will pay more attention to this process. Now, let's finally start retouching.

Next: Retouching basics


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