Hard light

(See Blending modes)

Healing brush

This was one of the most exciting features to appear on Photoshop 7.0 and is located on the toolbar where the airbrush tool used to be. The healing brush is a glorified Clone tool and does a fantastic job on some things and makes a hash of others.

I would suggest that until you are familiar with this tool you can always try it first and if it doesn’t work, undo the action and switch to the Clone tool.

The reason it’s excellent when it works is that it takes the sample from the area you first select, just like the Clone tool, but when you paint over the area you are repairing the sampled pixels are not just laid down. The program looks at what you are cloning over and blends the two. In the photograph of a lime (right) there are a few blemishes.

I’ve sampled from a lighter area (highlighted in the red circle) knowing that if I tried cloning from here with the Clone tool it would produce a glaringly obvious patch (middle).

When the healing tool is used to sample from the same area it ensures the original pixel color and density are not lost.

If the area to be ‘healed’ had been a larger area of black then the original pixels would have influenced the result and it wouldn’t have done much to cover the blemishes. Overall it’s a stunning bit of technology that I’m sure will find its way into the competitors’ products soon.

A close-up section of a scanned Polaroid Instant Black & White slide. As you can see it’s a very dusty example. This would be very slow to sort out using the Clone tool, but this area took just over a minute using the Healing brush.

Sometimes it helps if you make a rough selection around the area that you want to heal. This prevents surrounding pixels affecting the blend. Top is the result of no selection and the bottom version is with the middle selection.

Make the source Pattern (activated from the options bar) to heal an area with a preset pattern. The pattern blends into the picture. Here I’ve turned the flower into a piece of Bridget Riley op art using the Darken blend mode.

Here’s where the Healing brush (bottom) is far more practical to use than the Clone tool. Try removing the couple of blemishes using the sample point indicated with the Clone stamp and you will create light blotches.

Help

Photoshop CS’s help menu has a bright interface with plenty of topics covered to ensure you understand the program and its functions. Each section is split up to make it easy to find. There is plenty of ‘how to’ material and a useful search. As well as linking to all the stuff provided on the CD that comes with the program, it goes direct to the Web as an extra resource. This ensures we can keep on top of the program and receive any updates that Adobe throw at us.

Highlights

The brightest parts of the image with detail that will still print. These can be adjusted using the clear triangle on the slider control that appears on the right-hand side of the Levels graph.

Histogram

A graph that plots the image in a series of pixel values from 0 (black) to 255 (white) and looks like a mountain range profile.

The horizontal scale represents shadow to highlight detail and the vertical axis is the number of pixels at a particular point. You can view the histogram of each of the RGB channels individually or as a group. It’s used to check whether your image is suitable for printing and can be edited in the Levels palette by adjusting highlight, shadow and midtone sliders.

(Located in Image menu on earlier versions of Photoshop)

A low key image appears with most of the peaks concentrated in the shadow area at the left-hand side.

A high key image has the peaks in the highlight area to the right.

The average tone image should have a graph that rises from the far left, peaks across the middle section and falls to the far right.

History brush

Use this to paint in details from a previous stage of editing. Click on the box that appears in the History palette at the stage in the image editing process that you’d like to apply and paint onto the new level.

This is a great option if you’re considering hand-coloring a black & white image. Cheat by starting off with a color image and convert it first to grayscale to discard all color information and then back to color. The black & white image can then be colored using the History brush. Click on the left of the opening image to turn on the History brush icon. Then click on the latest stage and begin to paint.

Also good for removing dust and scratches. Apply the dust & scratches filter and make the history brush active on that new layer. Then go back to a previous history level and paint with the History brush over dust & scratches to paint in the newer filtered layer.

History palette

Every task you perform in Photoshop 5.0 upwards is recorded as a step, or state, in the History palette. This allows you to go back up to 100 previous stages when an image you’re working on starts to go wrong. A slider on the left-hand side can be dragged slowly through the stages to help you find when things start to go wrong. Simply click on the last stage that you were happy with and start again to change history – if it was just that simple in life!

Hue

Hue is the image color and varying the Hue slider changes the overall color. The scale runs through the colors of the rainbow starting at the left with blue. This cross polarized picture of a CD case shows the effect the Hue slider has over the color when adjusted in 30 unit increments. (See Blending modes)

Hue: 0 (original)

Hue: +180

Hue: +150

Hue: +120

Hue: -30

Hue: -60

Hue: -90

Hue: +90

Hue: +60

Hue: +30

Hue: -120

Hue: -150

Hue: -180