Thursday, December 24, 2009

Changing Backgrounds using Replace Color

This first tutorial is a very basic one using Adobe Photoshop Elements 2.0! The reason for this is that i would like people starting out to get a good grasp of layers and the basic tools that the earlier versions of photoshop had, on which all the high end work was done a decade back. Being a 'manual gear-shift car' kind of guy, i believe one can never go wrong with an 'auto geared' vehicle! 

Anyway, this image of my pretty model Andrea, was shot on a white background with one beauty dish. To see how to light this image, go here. Usually for 'cutouts', its always a good practice to plan ahead what the background will be, and shoot accordingly. So, if you have to put the model against a bright sky, then use a lightest shade of gray or off white for the studio background. Some people use green/blue chroma screen for backgrounds but after experimenting with those, i would suggest to use neutral colors for still photography as they don't leave a harsh green/blue tint on the skin tone(which ofcorse is correctable but extra work).


We start by copying the background layer and making a duplicate copy of it. This is done by clicking and draging the layer over the 'make new layer' icon. Now between these to layers, paste a layer you want as your new background, which in this case is a sea/beach image. If it pastes on top, simply drag it between the two to make a 'sandwich'. This a technique forms the base of understanding layers and masking in photoshop. Layers were introduced with photoshop3 and you will be amazed at how complex images can be created with multiple layers. Select the top most layer of the model and with a lasso tool make a quick outline selection. Pressing and holding alt/option key will let you make a freehand selection. Inverse the selection by pressing Ctrl(command for mac) Shift and I all together. Delete the selected area from the layer by hitting the delete key. Press Ctrl(Cmnd) D together to hide the selection and get rid of the marching ants.


Now select Replace Color from Enhance>Adjust Color>Replace Color from the top menu bar in Photoshop Elements. (PhotoshopCS users go to Image>Adjust>Replace Color). Use the color picker as shown in red circle, and select the lightest shade of the gray patch surrounding the model. After that, crank the lightness slider to the max. Adjust the fuzziness slider to make sure hat most of the gray patch becomes white, but not affecting the model. Hit OK when its done. You will see that most of the gray area turned white, but still not pure white. There will be shades of gray here and there. Lets see how to remove this in the next step.


Create a duplicate copy of the current layer where we just applied replace color. Now, select this new duplicate and again select Replace Color from Enhance>Adjust Color>Replace Color from the top menu bar in Photoshop Elements. Now use the color picker, and select the darkest shade of the gray patch surrounding the model. Increase the lightness slider to make it completely white. Use the fuzziness to control it from spreading the lightness to the model. This time the importance has to be given to make the patch completely let the models skin burn a little bit. After pressing OK, select the eraser tool. Use a soft edged brush with 50% opacity (note: this is the brush opacity and NOT the layer opacity) to erase the burnt out areas of the models skin. What this does is it reveals the not burnt (or in other words, perfectly exposed highlights) from the underlying layer below. See the erased area on the screenshot below...

 Yes, another example of masking without really creating a mask. Now merge these to layers by selecting or linking them together and pressing Ctrl(CMND) E to get the following image:


Easy so far? In this step get ready for some heavier masking! Start by creating one set of duplicate layers of the model and the beach background and arrange them as shown in the screenshot. Now select the top most layer of the model and change the blending mode to multiply. 

This is one of the most important blend modes used for compositing, along with overlay. What multiply does, in lay mans term ofcourse, it blends the lighter areas in the image with the layer below it. So.....the white areas will vanish and blend in the beach image. The hair strands will blend in perfectly too, without even having to cut it out. So you see, thats why we were making the gray patch white. If you ask me, why i didn't shoot it in a white and lit background in the first place....i have to tell ya...that made me come up with the tip of PLAN BEFORE SHOOTING!

OK, so while the white patch dissappears, so does the highlight areas of the model. Merge this set of model and beach multiplied layers into one. Now this next step requires skill, so practise with your mouse or stylus to get a nice control of freehand movement. Thats how the pros do it. Countless hours of masking, with differnt brush sizes. There is no shortcut for perfection! Anyway, select the eraser tool and simply erase the affected areas of the model to reveal the clear image of the model below. Use large brush sizes to cover large areas and smaller for small areas. Also, make selection with lasso tool and then erase tricky areas. Notice how the final erased layer looks in the screen shot below.


Once when you are sure there are no more corrections, merge all the top 3 layers. By now, you already have the final product. But lets spice it up a bit. Select lighting effects from Filter>Render>Lighting Effects and select Omni lighting. Make the area of the circle big and slect the light color to sea green like shown. The color should be from the pallete of your image. You can try other colors too, just for kicks. Use the intensity slider to control the brightness of the light. Be careful not to burn the image. Pressing Ok, will add a nice vignette in the image. The importance of this step is that it makes the composite look seamless and directs the eye to the subject first.

Now this is the final image:

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