Photoshop CS5 beginner question about History Brush

[Ichinisan]

My sister is getting frustrated with her Photoshop CS5 for Dummies book. There's a paragraph that tells her how to do some effect with the history brush where you make an image black-and-white, then "paint" color into parts of the image.

Here's one example of using the History Brush as a creative tool. You open a copy of a photograph in Photoshop. You edit as necessary. You use the Black and White adjustment on the image to make it appear to be grayscale. In the History panel, you click in the left column next to the step immediately prior to Black and White to designate that as the source state, the appearance of the image to which you want to revert. You select the History Brush and paint over specific areas of the image to return them to the original (color) appearance. There you have it -- a grayscale image with areas of color, compliments of the History Brush!

It doesn't work. As soon as you try to draw on the image, there's some annoying error message about a layer or channel. If you have Photoshop CS5, can you try to do what's in the quoted paragraph and let me know if you get an error message?

 

[jhansman]

Go to Adobe TV and you should be able to find video lessons on many features in PS, including the History Brush.

 

[Ichinisan]

Go to Adobe TV and you should be able to find video lessons on many features in PS, including the History Brush.

Is there something missing or incorrect in the statement I quoted from her book?

 

[nboy22]

I see the problem. It is saying something like "you must rasterize the layers first before you can do that method." So basically what you'll need to do is go to the layers panel, you should see the black/white adjustment layer on top of the photograph layer. Select the Black/white layer from that layers panel, and use the shortcut CTRL+E to merge the layer down. After that, it should work.

Explanation:

There are two different forms of imagery when it comes to graphic design. Vector graphics and Raster based images. Raster images are the common web graphics you see that when blown up to a bigger resolution, you will start to get pixelation. Vector graphics are graphics based on equations (generally they look more cartoony because they are drawn in adobe illustrator). These Vector graphics can be blown up to infinite size and never pixelate.

The method of using a black/white adjustment layer must be triggering some sort of vector graphic based workflow, so the easiest way to resolve the issue is converting everything back to raster-based imagery. That's why you use the CTRL+E method to merge the layers back together.

 

[BarkingGhostar]

Hmm, I would like to try this out, but I'm not buying the Dummie. I'm ignorant, not dumb.

 

[rivan]

The method of using a black/white adjustment layer must be triggering some sort of vector graphic based workflow, so the easiest way to resolve the issue is converting everything back to raster-based imagery. That's why you use the CTRL+E method to merge the layers back together.

It's nothing vector, it's just that as an adjustment layer, it's only modifying the pixels beneath it, not putting any actual pixels on a layer. Thus, there are no pixels to step back to with a tool like the history brush.

The rest of what you said is correct.

I would add, however, that CTRL+E (merge) will commit the change to the layer permanently - undos and history will work until the image is closed, but not afterward. As a personal preference, I (almost) always leave an untouched version of the original image for future use. To this end, I'd duplicate the original image, then merge the adjustment layer to the copy.

Edit: OP, are you using a Black & White Adjustment LAYER, as assumed by nboy22? Or the Black & White ADJUSTMENT? They're likely the same (or very similar) but they're different ways of getting to the same end result.

The adjustment should not give you an error. The adjustment layer will behave as nboy22 mentioned.