Adobe PhotoShop

for the Web Tools Review by Philip Greenspun

PhotoShop is the world's best image editing program. You can learn the basic image cropping and color/intensity adjustment commands in a few hours. You can spend the rest of your life learning to become a PhotoShop artist.

This page doesn't really do PhotoShop justice right now, but I hope you will contribute (send mail to philg@mit.edu if you are willing to write something)...

Pointing

If you can't tell PhotoShop which pixels to edit and how much to change them, you're dead in the water. All serious PhotoShop users have drawing tablets. My favorites are made by WACOM. I used to have one of their 12x12" tablets, but I find that the ARTZ 6x8 II works better and is big enough. It is much harder to point precisely with a mouse, but if you are determined to try, then invest $12.95 in a 3M Precise Mousing Surface. I always thought mouse pads were worthless but this one made me a believer. It has micro bumps on which the mouse rides for better friction, high above the "dust, dirt and hand oil" repulsively described in the packaging. It is small so that you don't rest your filthy paws on it. It is slim so that when the mouse rolls off the pad it doesn't fall off a cliff. These 3M guys are geniuses. If they wrote operating systems, Bill Gates would find himself pumping gas.

Memory Management

Starting in the 1960s, computers were equipped with virtual memory. This would allow a program to work with data larger than the computer's physical memory by swapping data to and from a (larger) disk drive. PhotoShop was designed for MacOS, an operating system that originally lacked this feature. Consequently PhotoShop has its own implementation of virtual memory. These days, even the MacOS and Windows95 have moved into the 1960s and provide virtual memory. Nonetheless, because PhotoShop understands its data better than the operating system would, Adobe has kept their proprietary virtual memory system.

On the Macintosh, this works pretty well. You turn off the operating system's virtual memory. You give PhotoShop 48 MB or whatever. PhotoShop does the rest.

On Windows NT, you can't turn off the operating system's virtual memory. There is no "back to the 1950s" control panel. However, an individual program can request "wired pages". That means that the operating system will give PhotoShop a page of real memory and promise not to swap it out to disk. PhotoShop requests a huge block of these pages and then does its own virtual memory thing just as though it were back on MacOS. There is nothing really wrong with this except that it is hiding behind your back. You have to go to File->Preferences->Memory to see that PhotoShop by default is grabbing 75% of your RAM and wiring it down.

Why should you care? Because if you have a wimpy NT box like mine with 64 MB, PhotoShop turns it into essentially a 16 MB NT box. A 16 MB NT box thrashes because the operating system itself takes up more than 16 MB. Most NT applications won't affect performance if you haven't used them for awhile. Their pages are swapped out to disk and stay there until you pull the app off the task bar. However an open PhotoShop will continue to hold down those wired pages even if you haven't touched an image for days.

Bottom line:

Resources

philg@mit.edu

Reader's Comments

In addition to the 3M Precise Mousing Surface, I've found the Microsoft IntelliMouse Explorer mouse lets me mouse very precisely. Best of all there's a lifetime warranty _and_ there's no moving parts to dirty.

A small addenum... after a few months of using it. Yes, one part does get dirty -- the little "feet" that hold the mouse up... but they're easy to clean -- you just have to rub them with your thumb and any grime goes away. Much easier than performing mouse surgery for cleaning :)

-- Dominik Rabiej, March 15, 2000

If you want to use a mouse in photoshop I recommend you consider some of the better gear for computer gamers. Specifically, consider getting an optical mouse from either Microsoft or Logitech. Even though you don't need a mouse pad with one of these I'd highly recommend one, the latest and greatest are made by EverGlide, RatPadz, and fUnc Industries. The are indestructable, look great and allow optical mice track with incredible precision. Finally, a Mouse Bungee will let you forget about that nasty mouse cord that is always snagging at just the wrong time.

-- Michael Olson, August 27, 2000
In general, I agree that Wacom's tablets are great, but my biggest problem with them is they keep changing pens every year or so! I would buy many more Wacom products if they were not so quickly obsoleted. I now have three tablets and three pens (ArtZ, Graphire, and Intuos), all of which are incompatible with each other! I'm not about to run out and spend ~$80 for an airbrush or second pen, knowing it will be worthless with my next tablet. Nor will I buy the new Intuos 2, now that tech support told me THOSE pens were incompatible with my other three tablets! I do like Wacom, but they need some competition! I realize that technological improvements sometimes necessitate obsolescence, but I think a bit more regard for backwards compatibility would be good for both the graphics community and Wacom's sales.

-- Jan Steinman, November 25, 2001
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