Photoshop in practice.

I like to work with an uncluttered screen so I usually switch off all palettes with the Tab key. The Info palette is under F8 and the Layers palette under F7. The only problem with this is that it switches the Status Bar off. This shows a very useful feature. Click on the right facing black arrow towards the left of the bar, then select Scratch Sizes. This shows you the amount of RAM available and the amount in use. When the RAM overhead reaches the available RAM the whole thing will slow down, either save the work and re-open or go to Edit-Purge-All-OK. That gets most of your RAM back.

The default palette layout in PS is not the most useful for most amateurs and especially astro amateurs. Things like Paths, Style, Swatches and Colour have very little use in astro work so they should all be closed. Re-dock Layers, Channels and History together. Layers will always come up under F7 and in this case History and Channels will be ‘attached’ to it. This way you can help maximise your screen space and use it for the important bit, your picture.

As mentioned above, the Info palette is under F8 and should pretty well always be on. You cannot determine small changes of colour, contrast or brightness by eye especially as this depends heavily on the ambient light falling on your monitor. Pretty well all astro work is done in RGB so the first readout on the info palette should be RGB! The second readout is often left to CMYK or something equally useless. Set it to HSB and you then have an immediate way of seeing colour changes as you mouse over the picture. The Hue reading is based on a colour wheel that goes from red through yellow, green, cyan, blue and magenta. You can of course see this in RGB but with HSB you can also see brightness on a scale of 0 to 100%, a very useful way to help set the background brightness of the picture.

Before starting go to Preferences, Memory and Image Cache and set the RAM slider to about 90%, I believe the default is 50% of available RAM so you get a lot of extra RAM for nothing.

On the Display and Cursors tab check ‘brush size’ and ‘precise’.

Remember that with Curves the corners represent the Black and White sliders in Levels. With Curves you can place up to fourteen adjustment points making it just a bit more sophisticated than Levels.

The Curves dialogue will be used extensively so set it up so that you can see it. The standard box is quite small so click at the bottom RH corner and it will get bigger. Alt-click in the graph to reset it to ten squares instead of four. This helps to give the feel of more precise control and makes it easier to use. See below.

You can make all your adjustments in the form of adjustment layers but I rarely do this. It is so quick to go back to your master, ‘Save As’ a new name and do it all again that I cannot see the point.

You can use all sorts of Layer techniques in processing but you must keep your eye on the ball. Do they really help or are you becoming seduced by technique for the sake of it?.

Suppose you want to set a neutral background near, say, the edge of a galaxy. Go to that place with the cursor, Ctrl M for Curves and then Ctrl-1 for the R channel. Without moving the cursor Ctrl-click and an adjustment point will appear on the curve in the right place. Watch the Info readout and move the curve with the arrow keys. Set the value to a loose average of the three. Do the same thing again with the G channel (Ctrl-2) and then again with B (Ctrl-3).

After each initial move you should reset the curve at its higher or lower points so as to return it to a straight line. Use the X-Y readout on the Info palette to return to the same place, set it to read Pixels. The Curve can generally be straightened by going to the required grid intersection and merely clicking, the curve will snap to the cursor unless it is a long way away.

There are many keyboard shortcuts in Photoshop. In general they are designed to speed things up but even if you have all the time in the world they can make things go much more smoothly.

If you want a new layer simply click on the new layer icon at the bottom of the layers palette.

If you want a duplicate of the active layer simply drag it onto the new layer icon.

If you want to combine two pictures select the Move tool and drag one picture into the other. This works with selections as well. Hold down the Shift key and the layer will automatically be centred. No more cutting and pasting.

If you want to convert a colour picture into mono, perhaps for use as a luminance layer, go to Image-Mode-Lab colour. Select the Lightness channel and then go back to RGB discarding the colour info. This generally gives you a much better read of the contrast.

One very useful one to finish off, With almost any tool selected, and some of them can be very hard to see, the Ctrl key toggles to the Move tool which is much more visible.