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Sally Jane Photographic Art

Adobe Photoshop Tutorial

 
 

Photoshop Layers Pallet - Adjustment Layers

If you are reading this then chances are you don't use adjustment layers. After reading this, hopefully, all that will change.

Adjustment layers are used when you need to make changes to your image for either contrast, levels or colour or anything that effects these. You may well be used to doing this by opening your image and clicking Image on the top menu bar, selecting Adjustments and then selecting levels or contrast etc. That certainly works but it is not a safe way of working. Say that after changing the levels in this way you then proceed to make several other edits to your image. You then decide that the levels adjustment you made was too much. The only way you can undo what you have done is to go back in your history pallet and selecting the stage just before you made this levels change. Any alterations you have made to the image since then will be lost and if you have made more changes than you have history stages available then your only option is to go right back to the beginning and start all over again. Frustrating and time consuming.

Adjustment layers get rid of that problem completely. When you use an adjustment layer that layers settings can be altered at any stage until such time as you flatten the image and so lose the layer. Complete versatility.

So, to get started. The first thing you should do once you have opened your image in Photoshop is to convert it into 16 bit mode. If you have not read the section on this now would be a good time. Look at the layers pallet. At the bottom there are a series of symbols. the middle one that looks like a disc half black and half gray is the icon for adding a new adjustment layer. When you click on it you are presented with a list of all the various adjustment layers available.

adjustment layer list

As you can see. The image I have open is horribly under exposed. I am going to select a levels adjustment layer to fix this. When you click on Levels you get the same window you would if you had clicked on levels under Image on the top menu bar, Adjustments, Levels. Basically it is a histogram but with little pointers underneath that you can slide in or out to select the black, mid tone and white points in your image.

adjustment layer

You can see from the histogram there were no white or even near white values in my original image do by sliding the white pointer in until the graph starts to rise I am not losing any data and nat causing any blown out areas. If I was to move the slider passed where the graph started to rise I would be creating white blown out areas or hot spots in my image. The same goes for the black end. The gray slider sets where mid gray should be in the image. It normally sits at a value of 1 but by sliding it towards the black end of the scale you will lighten the mid gray tones and by sliding it towards the white end you will darken them. This is useful if you want to bring out shadow detail. I have moved this gray point to the left, black end, because the walls of the church were too dark. You can also use the dropper tools to set the values automatically. If there is an area in the image you want to set as black you can click on the black eye-dropper and then click in you image where the black point you want to select is. Same with the white. I seldom use these but instead I often use the gray eye-dropper as this is very useful for correcting white balance issues. This will be explained in a later tutorial.

adjustment layer

Above the histogram there is a drop down box in which you can select individual colour channels. I though my original image was a lacking in colour. I could create a separate adjustment layer for hue/saturation or colour balance to correct this (either could be used) but this levels dialogue will allow me to do it here also. Now the white slider represents blue and the black slider it's opposite which is yellow. By moving the blue slider in I can enhance the blue in the image which brings out the sky nicely. By moving the yellow slider in I can add more warmth to the stone walls. You need to remember which colours are opposites as it only gives you one of the colours in the list but for your info, Red controls Red and Cyan and Green controls Green and Magenta.

Below the histogram you will see a slider and a couple of number boxes entitled Output Levels. This is useful for optimising your image for your printer. I do not set these when editing my images initially but only use this before printing and especially on certain papers if I think the printer will not be able to handle the dark shades. More about this below.

layers

Once you are happy you have made all the changes you need click OK. You will see in the layers pallet you now have a new layer which in this case will be called Levels. If you click on the thumbnail it will return you to the levels dialogue box and you can see all the settings you made and change them if you wish. You can do this at any time during your work on the image no matter how many other layers you have created or edits you have made. You will also notice there is a white thumbnail in this layer in the layers pallet. This is a layer mask and it is white which means it is inactive. By painting on this in black you can disable the effects of the adjustment layer in areas on your image where you might not want it. See the tutorial on Layer masks for a better explanation. You can also use the opacity slider at the top of the layers pallet to lessen the effect of the adjustment layer just as you can with any other layer.

There is no limit to how many adjustment layers you can have. I often work with multiple as you will see in the example right. You could say from this I am a layers freak but I like the total flexibility it give me and the knowledge I have not wasted any effort if I later decide I don't like it or it needs to be changed. By clicking on any of these adjustment layers I can fine tune them until I am totally happy.

One thing to note, however, about my set of layers in this image is that I have been a little sloppy in not giving each of my layers a descriptive name. That can get a little confusing when working with multiple layers so it is always best to name them as you go. Layer 1 or Layer 2 does not tell you what is on it.

Output Levels and printing.

The colour gamut you monitor can display varies from monitor to monitor. By this I mean how many stages of lightness values it can show between 0 and 256. Few monitors can display them all so the maybe 256 to 240 all appear black for example. Printers are generally worse than monitors in that they often have a much narrower range. This will also vary depending on the paper used in the printer. Knowing your printer and how it performs with various papers is important particularly when printing dark images if you don't want all the shadow information to just turn out black. This is where the Output Levels slider comes in very useful. It changes the black or white point for printing. By adjusting this it will show in your image which is why I don't save images with this adjustment in place. I only make this change before printing and then remove the adjustment after because the next time I print it it might be on different paper which needs lees adjustment. Dragging the black slider in will appear to lighten your image. This will allow your printer to print the shades within the darker areas rather than printing them all black. How much to move it will come with trial and error. I know for printing on my proofing paper I need to move the black slider in until it read 20. For final images printed on Archival paper I don't need this adjustment at all. If in doubt, print a small strip of your image cutting through the dark areas. Allow it time to dry and then check it closely to see if you can see the detail, if not, move the slider in and try again.

OK so we have talked about adjustment levels with respect to Levels but you can select any of the options and they all work just the same. Remember the best way to see what they do is to experiment.

Hot Tip - Super fast selections using adjustment layers.

If you want to replace a background but don't really want to spend ages masking the subject because it's just too fiddly then this is the coolest trick ever. You do need a good contrast between the subject and its background so it can't be used for all situations. The photo above of Oviedo Cathedral is an ideal candidate. The sky in this image is overcast and dull even after changing the levels. It would look far better with a better sky but trying to get all that fancy stone work of the spire cleanly separated from the background could be tricky. It actually takes me just a few seconds. With the image open I click on the New Adjustment Layer button at the bottom of the layers pallet and select Threshold from the list. This separates out light from dark areas in the image and there is a slider so you can control where the cut-off point is. I slide the slider until all the building is black and all the sky white. Then I hit OK. You now have a two tone image. Use the magic wand tool to click on the black building and it instantly selects it all. If you need to tidy it up you can by clicking on the Quick Mask icon in the tools pallet and either painting in areas that should be masked or erasing areas that shouldn't. I didn't need to do this as my selection appears perfect first off. Now turn off the adjustment layer so you are now looking at your original image with the selection in place. Click on the Background layer in the layers pallet to make it active and either hit ctrl+j or go to Edit-Copy followed by Edit+Paste into (paste by itself won't always place it exactly where you want it). The building has now been copied to a new layer. Now I open up an image of a beautiful sunset. Using the move tool I drag this image onto my Cathedral image and then change the position of this new layer so it is between the Background layer and the copy of the building. Edit-transform-scale will allow me to alter the size of the sky so it fits. For a finishing touch I blend the hard edges of the cutout building by going to Layer on the menu bar - Matting - Defrindge. I select just 1 pixel and hit return. Now the image is ready to be flattened and saved. Simple.

Still not sure? Watch the video below, no sound but I do exactly as I have just described so you shouldn't have too much trouble following it.

 

 

Video - Using an adjustment layer to make a quick selection

See also

Black and White Conversions using the Channel Mixer Adjustment Layer

 

for further information on using layers check back in a few days or alternatively here is an index of other tutorials involving the use of layers.

Blur - Applying Gaussian blur

Frames - Adding frames to your image

Sharpening - Selective sharpening using a layer mask

 

Recommended Further Reading for Photoshop

 

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"A-Z of Digital Editing"

  

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