CGNest Blog

So you rendered an image that you need to send to a client. And its a beautifull product design that needs to have a white background. But you forgot to render and alpha pass to remove the background or you have a situation where you cannot render with alpha from your 3d package and it absolutely needs to be white. So you call photoshop to the rescue

You can do all sorts of things in photoshop, you can clone the background, you can take a brush and just brush out the colored parts, you can crate alpha maps but i found a really simple and effective way to do that in photoshop.

So here is an image that has almost white background but not completely white.  A great tool in photoshop to quickly make it white is called “Replace Color..” You can find it if you go Image/Adjustments/Replace Clolor… Now when you click on that you get a dialog that looks like this

First thing that you are interasted in here are the 3 color pickers. The first one is for the general color. You need to pick the background with this. So you click on an almost white part of the background with it and you get something like this.

Now the preview image is diferent. What this is telling us is that the white parts of the image will be affected and the black parts will not. We are almost done here. But nottice that in the upper right corner of the image we still have some parts that are not completely white so they will not be completely affected. So we need to add those as well. Select the middle color picker and pick that part. This color picker is for adding aditional clolors to the selection and the last clolor picker is for subtracting colors if you over did it. After we selected the remaining part we should get something like this.

One thing that i found really good about this method is that the shadows are fixed very very good.  When removing the background with a brush or cloning you can see where you have brushed in the shadows but not with this method.  Now all we need to do is crank the lightness slider all the way to the right and we are done!

I hope that you find this tip usefull.

Cheers!