The following are the top 10 tips

It’s rarely easier to “fix it post” using Photoshop. If you know that you are going to photograph an object at a different angle or with different lighting, move the camera, the lights or the object in real time. This will save you countless hours of post image capture manipulation. Similarly, if you know that you are going to be removing an object from it’s background, try to shoot it against a similarly colored backdrop under similar lighting conditions. Or, if you don’t know where it’s going to be compositied, then shoot it against a solid color that is easy to drop out such as a blue screen. Try to shoot the image with low contrast you can add that in later. Don’t get lazy – Photoshop is not an excuse for bad photography.

One of the reasons that images don’t look right together is that he grain structure or amount of digital noise from a camera is different. To create grain to match images, create a new layer above the image that has less noise and fill it with 50% gray. Group this gray layer with the previous one and set it’s blend mode to Hard Light. Select Filter > Add noise and use the slider to add the amount of noise necessary. Creating the noise has the advantage of being non destructive in it’s edit, and also can be scaled using free transform to make the size of the grain larger or smaller to match the size of the grain in the other images.

There are many composited images that have very odd depth of field going on. If this is the look that you’re after, great. However, be sure to pay attention to the object in the foreground and background of images and make sure that the depth of field is the same for all images being composited. To change the depth of field, use the Gaussian Blur filter. To achieve a natural looking affect, it might be necessary to run the filter at differing values to multiple copies of and image and use layer masks to selectively show and hide the blur amount that is needed in certain areas of the image.

There is nothing that will give a post composite away faster than two images that are not color balanced or have been shot under different lighting conditions. If you’re trying to put together two images where one was shot in mid day and the other at dusk, well, good luck trying to get the shadows to match! Many times this is “fixable” in Photoshop but can take a fair amount of time. Also, color correct the images to make them work together. If one image was shot in natural light, and the other in the studio, balance the colors to make it appear to be one image.

The Defringe command can be a real time saver in removing the halo from around an image. If that doesn’t work, try loading the transparency of the layer (Cmd (Mac)/Ctrl (Win) click on the layer in the Layers palette and then choose Select > Modify > Contract and enter a value as wide as the halo pixels. This tends to remove a bit of the fine detail so you might want to select a slightly larger number for the Contact, and then add a 1-2 pixel feather and see if that helps when working with soft edge images.

After creating a selection the edges of the mask might not be quite exactly where it needs to be. To fine tune a mask’s edges target the mask in the Layers palette and select Image > Adjust > Levels. Using the slider in the Input section, slide them to refine the edges.

Instead of adding feather to a selection and then adding a mask, try adding the mask, and then blurring it. Feathering (at least to me) is always a guessing game, since it depends on the resolution of the image and how soft the edge should be. Since I couldn’t always predict accurately, I discovered that bypassing the feather, creating the mask, targeting the mask in the Layers palette and then blurring the mask would give me the visual feedback that I needed to make an accurate edge for the composite. Not all areas of the mask necessarily need the same amount of blurring. To add small, additional blurring, use the blur tool, to add greater amounts, select the area of the mask to be blurred and then select Filter > Blur > Gaussian Blur.

If the image needs more contrast or another type of radical adjustment to help make a selection, add the adjustment with an Adjustment layer and then create the adjustment. After achieving the needed selection, throw away the Adjustment layer and work with the original information.

Sometimes it’s an advantage to have the tonal values of an image (without the color values) to work with. In order to “load” the luminosity of a layer as a selection use the keyboard shortcut Cmd + Option(Mac)/Ctrl + Alt (Win) and the tilde. With the luminosity loaded, changes to the tonal values can used as a mask and manipulated.

Don’t forget about shadows. Many a composite is ruined because an object is casting a shadow in the wrong direction than other objects in the scene or because it was left out altogether. If you’re creating shadows in RGB, then they will be separated for you, if you’re creating them in CMYK, be sure that you’re not creating shadows out of pure black, but are adding in CMY as well. Compare the densities and color of the other cast shadows and make them consistent. Don’t forget that as an object gets farther away from the shadow, it’s becomes softer both in edge sharpness as well as density.