Photoshop Question

[Esteban]

Hello,

I have a scanning and Photoshop question. It may seem basic, but I can’t seem to come up with a solution. Several years ago, I drew out a world map in pencil and pen for my campaign. Now that I am (somewhat) familiar with Photoshop (5.5) and own a scanner I want to add color and depth to my campaign map. However, when I attempt to scan the map I don’t get a straight black and white scan. Even though I’m scanning in black and white, my map comes out in black, white, and several variations of gray making it difficult to do fill-ins and backgrounds. I wasn’t totally surprised by the scan result, but I’m finding it hard to get around it. Does anyone have tips for scanning in black and white images so that they can be easily color filled? Any help would be greatly appreciated.

Thanks in advance.

-Steve

 

[Kid Charlemagne]

By coincidence, I'm doing the exact same thing right now!

You might be able to reduce the gradation in grayscale to a minimum level to try and force the program to decide if an area is "black" or "white." That migh do the trick.

On the other hand I think the best way to proceed is to do it the way I did: Scan your pencil drawing, make that one layer, then create a new layer and trace over the elements with the pencil tool. Then you can do fills much easier. Tracing my map only took a few minutes, although I wasn't tracing anything but the continental outline.

You can also use layers to "turn on" various map elements - I plan on having an accurate elevation map on one layer, and a pictorial depiction of mountains and hills on another layer, allowing me to pick which I want to display/print out.

 

[Fast Learner]

Step 1 is to clean up some of the gray. Go to Image=>Adust=>Levels. Click on the white eyedropper and then click on an area of your map that should be white but is instead light gray. You won't want to click on a dark gray here, just a light gray that should be white. Then click on the black eyedropper and click on a part of your image that is very dark gray but should be black. Lastly you can slide the middle slider (below the graph, aka histogram) left and right to try to get nice solid lines without much in the way of excessive dark areas. Click OK.

Step 2 is to truly make the layer black and white (it's close now, but there are still grays). Go to Image=>Adjust=>Threshold. Slide the slider left and right until you see the right amount of solidity in your black lines and click OK.

Now this layer is completely black and white, making for easy Magic Wand selections. Depending on how things went in steps 1 and 2 you may need to clean up the layer a bit, especially if any of the lines have breaks in them.

Note that an alternate way to do this that will probably look better in the end is to skip my Step 2 and just make certain that your Magic Wand has a tolerance of somewhere between 16 and 32. This won't make the layer pure black and white, but it will give you nicer anti-aliased black lines. (I included Step 2 so you'd know how to remove the grays from a black and white image.)

 

[Esteban]

Thanks!

Thanks for the help, guys! It was exactly what I needed.

-Steve

 

[CNS]

Photoshop answer

Try this out:

- scan image at at least 300 ppi resolution.
- in Photoshop, increase the image's resolution considerably- I use 800 ppi- the higher the better.
- change the image MODE to bitmap. This will remove all grays leaving only black and white. Having the high resolution helps prevent a lot of jagged edges that come from pure black and white. Up close the edges will appear jagged but when printed or viewed at print size that effect is minimized. If you really want a more anti-aliased effect try a little blurring
-convert back to grayscale MODE.
-reduce the resolution back to 300 ppi. 300 ppi is acceptable for printed material.
-now you should have a high contrast image- no grays.

For coloring:

-Change to RGB mode- if you will print it, select CMYK PREVIEW for a more accurate representation of what will print. You can use CMYK mode but the RGB mode results in a smaller file size and more vibrant color for "computer screen only" images
-SELECT ALL and COPY
-in the channels palette, creat a new channel and PASTE. This creates an alpha channel, this step helps in separating the black line from the white background
-DESELECT ALL
-command(MAC) click the new channel (I don't know what the PC version would be but hold the cursor over the channel name and press the command control, etc. keys until a little marquee appears near the cursor). This selects only the black artwork.
-Click the RGB channel-this is to make sure you aren't working on the new alpha channel. The RGB channel should be highlighted.
-PASTE- a new layer should appear containing only the black artwork with no white.
-Change this layer's mode to MULTIPY- this will reduce any fringes that might appear.
-Work in the background layer. Now you can add color in the background layer and not obliterate your black borders since they are isolated in their own layer.
-To pick areas to be colored you can use the magic wand to make selections in the black line layer or the alpha channel. Make your selections in the black and white layer or channel but always make sure you are working in the RGB channel and Background layer when coloring. GROW the selection a little to help reduce fringes.
-If you have made an area selection that you want to keep, choose SAVE SELECTION this will create a new alpha channel that you can command click whenever you want to activate that area selection again. These channels can also be edited: just select the channel view icon (the eye next to the channel name) the channel should show up in a color, probably red- then highlight the channel name and begin painting or erasing similar to quick mask mode.
-the most important bit of advice I can give is always save your work and save it often.
-Again, when switching between channels and layers like this it's easy to make mistakes. Always make sure you are working in the Background layer and RGB channel when coloring.

I hope this helps. Right now this might look like a lot, but the more you do it the faster it gets and I'm sure it will get you the results you want every time. This is similar to the way most professionals do this kind of work.