Expert: Scott Valentine - 8/25/2008

Question
Hi... I'm a painter and not that great with computers but have to use photo shop
for different projects. Duh... how do I scan a black/white line drawing and have
it be transparent (ie white pixels don't print). Also, how do I crop an irregular
shape and remove the back ground? Honestly, I'm so exasperated I could burst!
I will be so grateful if you can explain it to me simply. Thank you, Katherine

Answer
Hi Katherine,

I think the best solution for you is to join a Photoshop forum where you can get ongoing help in a format that is more suited to discussion. That being said, here are the essentials of what you need:

Scan your line art as normal, and bring it into Photoshop at the highest resolution you need (or your computer can handle). With your line art in the Background layer by default, double-click on the layer thumbnail (make sure you have layers visible - check the help files for showing the layers palette/panel) and click "OK" to make Background a normal layer. Double-click the thumbnail again. Now, you should have a dialog box that gives you several options.

Near the bottom of the box are some sliders labeled "Blend If..." These little gems are going to make your life very easy. Notice there are two tracks, one called "This Layer" and another called "Underlying Layer". What these two sliders do is selectively lower the opacity of pixels on the current layer based on either the current layer's content, or that of the layer below. Since there is nothing below, you will be creating a transparent area.

Using the slider labeled "This Layer", move the right-most triangle to the left a little at a time, watching your image. You will see the lighter, white areas disappear. Unfortunately, this can leave you with jagged edges. Holding down the Option or Alt key, click one side of the triangle and drag it slightly away. You have just "split" the slider, which allows for a soft transition between the white and dark areas. Once you do this, you will be able to understand how to control the effect.

If your image is not quite white, you can use levels and curves adjustment, or a number of other techniques to prep the image for the above trick. Again, a forum is a better place to go into detail on this work.

Your 2nd question can't really be done easily. The problem is that you can cut out an irregular shape, but the image format you save or export to determines whether you can actually have transparency or an irregular boundary. Only PNG and GIF formats support these features currently. However, there may be other methods available to you depending on what you want to accomplish. Yep; hit a forum for details.

The forum I recommend is http://photoshoptechniques.com/forum

I am an admin there, and can vouch for the level of professional skill available. The community is focused on learning, so there is precious little ego or attitude. Perfect for getting your Photoshop wings!

I hope this helps. Please let me know if you have further questions :)

-Scott