Depending on your version of Photoshop you may have numerous options available for replacing background that will provide a more efficient workflow than lasso and eraser tool alone.
This video link goes through selection tool options in CS5, but the Adobe TV website also offers numerous video tutorials that can help with making better selections and masks.
When replacing a background that's a solid color, a popular workflow is to use the Magic Wand tool, which selects pixels based on color, to select the background and then modify the selection as you wish to change the color. Another option is to use the Quick Select tool, which automatically detects edges in an image. Selections can be further fine tuned by using the Refine Edge feature.
It may take a little time to learn these different tools and what's best, but if you're dealing with a lot of photos it's almost certain to take less time then running through everything with manual lasso drawing and erasing backgrounds.
Hope this helps!
Depending on the complexity of the background, the magic wand tool, color range tool (found in the select menu), quick mask tool. Each one has its uses and its falts, but all of them will create a selection that you can turn into a mask. Because the selection is editable, you can use other selection tools to make the selection more accurate.
What I have tried doing is this, I load the original photo. I then select a solid color white fill layer. I then chose eraser and alternate between that and brush to restore the head of the individual that I need.
Then backround is solid white. It is a little tricky erasing around the face and hair but alternating diameters of brushes and eraser seems to help. If anyone can add any thoughts to this method I would appreciate it.
Did you watch any of the videos on adobe tv for selections and masks. If not go head and watch them, you will quickly learn that you do not need the eraser tool. reason is the eraser tool is a destructive tool. Selections and masks are non-destructive. Which means that should you change your mind any time later after closing photoshop, you can reopen the image and change it, including bringing it back to its original state.
When you using the quick mask tool, you can switch back and forth between the white color and black color just by hitting the lowercase x on the keyboard. Armed with that keyboard shortcut and [ ] keys for adjusting the size of the brush, you can make quick work of your selection.
If you get the chance to get CS5 you will be happy with the new selection tools, but we can leave that for another day.
Unfortunately I can't remember the tools that were available as far back as CS2. If you follow the other two suggestions for help I mentioned (posting the in the Photoshop General discussion forum or using feedback.photoshop.com) you'll get some more in depth responses.
In general, like Silkrooster mentioned, you might want to try using whatever selection tools are available as an alternative to the eraser tool, but there's no shame in doing what feels comfortable if it works for you. If you haven't checked the Photoshop help manual yet (did they still offer a paper copy of it back then?) that might be worth a check, as it has a whole chapter that goes over the use of "Selections and Masks".
Good luck with your project!
You're right, I shouldn't imply that using the eraser tool is wrong, cause its not wrong. But for a new user it makes sense to keep the image non-destructive, just in case a mistake is made.
However, if someone is paranoid about making a mistake, they can make a physical copy of the file and work on a copy, the original can be place in another folder if they need extra protection. Or for the slightly paranoid they can just make a copy of the background layer (ctrl-j) and work on the copy of the layer ( this was the old style of learning and some still teach working on a copied layer).
So destruct or not to destruct is the question that only the user can answer.
While there are some neat new Tools in CS 5/5.5 for Selections, CS2 is still very usable.
I recommend using Layer Masks to isolate (mask) your image from the Background. This keeps pixels around your subject, just in case you ever wish to go back.
Basically, i use one of the Selection Tools, such as the Elipse, or Rectangle, or even the Lasso, but do a very rough Selection. I will refine that later on. Once that rough Selection has been made, I just Copy, and Paste into a new Image, with my chosen background. Then, I choose Select>Load Selection, and choose the default, Layer 1 Transparency. Next, Save Selection, and choose Layer 1 Layer Mask. Note: there are a couple of ways to accomplish the same thing, as with most operations in PS.
At that point, I have my Layer Mask, and click on the Layer Mask icon, to make it active (you can check that in the Channels Palette). The colors should change to black and white. Then, using various Brushes, you can "paint out" that Layer Mask, and can see your work. Use a good Magnification, and work slowly. Paint out the broader areas of the background from the subject in Layer 1, working down to closer and closer to the person. I start with larger Brushes, but might well end up with tiny Brushes, as I get closer, and closer.
The beauty of using a Layer Mask, is that you still have ALL of the pixels, from that initial Selection, so you can go back, and alter the Mask. As the colors are black and white, if you hit X, to swap the colors, you can then "paint in," removing areas of the mask, where you got too close. No pixels were harmed in this operation, and you can revisit that Layer Mask 10 years from now, and refine it.
The new Tools make that initial Selection a bit more refined, but you will still likely need to do some hand-work, and I'd just as soon have the pixels to play with, rather than use a Selection Tool, that trimmed out too many.
The time spent with your Masks, will translate to how realistic the composite is. It was exactly the same, back when we did analog compositing, and created Masks on Lith Film. After we were done, we'd go in with a "one-hair brush" and Opaque, to paint in the Mask, or with bleach, to paint out the mask. Now, it's just done with pixels digitally, and one has both the History Palette, plus Undo, just in case - unlike the analog days. Gosh, I love digital!!!!!!
Happy editing, and good luck,