What's it all about

This tutorial describes some of the tricks I have learnt on how to get Photoshop to run at its fastest by simply changing the way in which you work. I'm sure any of you out there who aren't running the latest nuclear powered computer (and maybe some that are) know that Photoshop can be voracious when it comes to system resources. Having to bend to what your computer wants to do, rather than what you want, can seriously hamper the creative process, as well as slowing down more routine work. So here is some advice on how to get a bit of speed out of your Photoshop.

Version

Ok, so firstly what version do you use? Generally the older the version the less system resources it will use, therefore if you are considering upgrading you should have a good think about whether you really need the features in the upgraded version. As an example, the increase in resources used between version 7 and CS is about 20% or so.

Customising Photoshop

Photoshop is fantastic for customising, whether it's custom gradients and brushes or more advanced 3rd party plugins there's almost no area you can't upgrade somehow. However it all comes at a cost in terms of performance. To make sure you aren't wasting your computer's processing power loading irrelevant things, get rid of extras you really don't need. This includes:

Brushes, patterns, gradients, styles, fonts, shapes and 3rd party plugins. Others like actions and tool presets use very little space so I wouldn't worry unless you have hundreds.

System resources

Photoshop gives you a little bit of power in terms of optimising its use of your computers resources. Go to 'preferences' (Ctrl-K), you should be on the 'General' page. History states is set to 20 by default, this is the number of actions that will be recorded in your history palette before they are purged.

Each one that is recorded takes up a chunk of memory. If you find that you generally don't need to go back a long way, consider changing this to 10 or so. To prevent yourself from making big changes and not being able to go back with this smaller history, use the Snapshot function when you reach important stages in your work.

Keep pressing the 'next' button until you reach the Plug-Ins & Scratch Disks page. This is really for people with multiple hard drives, but basically you want to make sure that the drives listed under 'Scratch Disks' have a fair amount of free space, and are preferably as fast as possible. The faster the disk is, the fewer slow-downs you will notice when Photoshop has to go beyond your RAM. You also want one that is accessed as little as possible, Photoshop likes to have disk space basically dedicated to itself. So if you have 2 or more drives, make the scratch disk the one without Windows (or your OS) on it.

Press the 'next' button again to reach the 'Memory & Image Cache' page. Now you need to decide how much of your RAM you want Photoshop to be able to use. This will depend on how many other programs you want to be running at the same time and how intensive they are. If you want to run Illustrator at the same time you have to take into consideration that it can use as much memory as Photoshop, if not more.

Personally I leave about 100mb free and dedicate the rest to Photoshop. Generally it's quite a good idea to set it above the default '50%' option unless you have less than 256mb of RAM. Beware not to set it too close to 100%, if you do this then Photoshop and Windows will end up fighting eachother over the RAM and it'll reduce your efficiency.

Efficiency

Try not to use more than you need. I love using hundreds of layers, but I find it can really start to hurt performance speeds after a while. I also work at at least double the resolution of the final picture so I can produce finer details, this certainly isn't efficient (4 x the size = a lot more memory + cpu power needed) but I feel the extra quality is worth it. However I try to make sure I get rid of layers I don't need as often as possible. Each layer you add is like opening another picture, adding to the amount of information Photoshop is trying to juggle, and thus the amount of memory it uses. The same goes for:

Layer styles - apply them when you don't think you need to change them anymore.

Channels - If you have created custom alpha channels for a specific purpose (as a map for instance) get rid of them once you have finished.

Paths - They don't use much space but it's still something.

Layer masks - These are basically channels, the more you have the more RAM you use. If you think you don't need to make changes to a layer's transparency any more then apply the mask.

Adjustment layers - By default they come with a layer mask, if you are using the adjustment layer to make changes to the entire canvas at once then simply discard the mask. You can add one back at any time if you need to.

Material outside canvas - Photoshop will store stuff in a layer even if it is outside of the visible canvas. Doing a select all > select inverse > clear will not affect this. The way to get rid of extra stuff is to do select all > copy > paste and then delete the original layer (You may need to change the blending mode and layer style of this new layer to match the old one however).

In addition to making Photoshop run faster, these changes will also reduce the size of the .psd.

Merging down

However efficient I am I often reach a point where there is just too much complexity in the file to continue, Photoshop grinds to a halt and I start running out of memory so badly I can't perform any filters/transforms etc. When this happens it's time to start merging down.

What you need to do is to work out how much of the picture you can merge while retaining the control you need (it's very easy to flatten the entire image to one layer but you might still want to reposition certain elements). You need to be careful when you do this to make sure you are not changing the image's appearance when flattening. Keep a snapshot before you merged and compare it to afterwards to see if you have affected it.

Things to watch out for when merging include:
Merging layers with different blending modes, merging layers with layer styles, merging layers with different layer masks or clipping groups, merging normal layers with adjustment layers etc. etc. I could probably write a whole tutorial about merging down while keeping the image consistent, really though it's a case of just trying different things.

I recommend building a few channels which represent selections of important objects, or layers, in your image, flatten the image and then use these channels to 'pull' the important objects out of the flattened image. Channels are not affected by flattening down.

Once I have merged down I generally like to save the file under a new name, keeping the old file with all the layers just in case I need to go back and tweak something. I used this method to build my site, I had merged down 10 times before I reached the final version, and if I wanted to make changes now I would have to hunt for the relevant layer in one of the 10 .psds I have. It's not ideal, but if I hadn't done this I would have 1 .psd with about 600 layers, my computer would choke trying to open that :}

Using multiple files to build an image

This is for particular pictures where you have very definite, separate elements. Say I wanted to use a picture of a car in a picture, but the car needed a fair bit of work first. I have to airbrush out imperfections, use several adjustment layers to sort out the lightness and colours, I need to give it a proper multi-layer shadow and reflection etc. etc. I could do all this in my main picture, and create 10 layers just for this one object.

Alternatively I could make a separate .psd, make the changes and then save the picture as a .jpg or .bmp and import this as a single layer into main picture. I leave this separate file as a .psd with all the layers intact, close it and can continue with the main picture without these extra layers being a strain on my system.

Again, a large number of the 'objects' in my site design were created on their own in separate .psds. I also made them at higher resolution than they needed to be, so that I could get extra details in before shrinking them down for the main picture.

Purging

This is a way of getting rid of the information Photoshop stores while you are working on an image (basically everything in the history palette and clipboard). If you don't really need what's in there, go to Edit >> Purge and you can free up some extra memory.

Well that's about all the tips I have for speeding up Photoshop, hopefully soon I'll have a much faster computer and not need to be quite so conscious of efficiency, but even with a fast computer I won't waste resources. I hope even if you have a fast pc you will have found some useful info here, and might speed up your work process as well as Photoshop.