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Sally Jane Photographic Art

Adobe Photoshop Tutorial

 
 

Photoshop Navigation Pallet - Histogram & Editing in 16bit Mode

In this tutorial you will learn how to limit the damage you do to your images when making colour, contrast or levels adjustments.

When you open an image in Photoshop the image opens in its own window and at the top of this window there is an image title bar. This gives you various bits of information including the colour mode and bit size. See image below.
image title bar

You can see that this image is a typical 8bit jpeg. I will be working with this image in the videos as it is a good example of a horribly underexposed image that needs some serious adjustment. Normally as you will see from the resultant histogram, this would be quite detrimental to the quality of the image but in the second video I will work with it in 16 bit mode and although not perfect, the difference in the histogram is obvious.

If you skipped the section explaining what an 8 bit or 16 bit image is, and you don't already know, read this section here first.

Below left is a full view of the image I will be working with. As you can see, it's probably a deletion candidate but fine for this example. It was taken on a very overcast evening so it was never going to be stunning from the start. The image on the right is the same image after I have adjusted the levels.

oveido cathedral oveido cathedral

As you can see, not a drastic amount of change but enough to play havoc with the histogram. You will see this in the videos but just so you can get a better look I have copied the histograms for you below. The one on the right is the resultant histogram after making the adjustment just in 8bit mode as normal and saving it. You will see it has loads of gaps in it which is not good. The histogram on the right is the resultant histogram after making the adjustment in 16bit mode and then changing back to 8 bit mode after flattening the layers but before saving it. Notice it is now more solid. OK so it's not as smooth as it should be but those little spikes are not a detrimental to the image as gaps.

histogram 8bit histogram 16bit

During the videos you will notice I keep refreshing the histogram. This is just for your information so you can see how it changes. You do not need to do this but you should once you have flattened your image so you can see the true effect.

 

 
 

Making a levels adjustment in 8 bit mode

 

Making the exact same levels adjustment in 16 bit mode

 

Remember this doesn't just work for levels but for any adjustment that involves tone, colour, hue, saturation, monochrome conversions etc.

 

 

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Tel. 07956 448690

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