Gradient Map
Black and White Conversion

The Gradient Map adjustment layer in both Photoshop and Elements may be one of the easiest methods of converting a color image to black and white and it does a wonderful job.

In addition to converting it is also possible to modify the contrast as well as tone the converted image!

According to the  help file, the Gradient Map filter maps the grayscale range of an image to the colors of a specified gradient fill.

 OK - what does that mean in real human Photoshop digital editor speak?

  • Grayscale range of an image - that's the Histogram.

  • Colors of a specified Gradient Fill - that can be any two colors in the Foreground and Background or colors you select in the Gradient Editor Dialogue.  Primarily the two colors will be the default colors, this is, black and white.

Here's the histogram from an image that was normally exposed and then tuned up slightly with Levels.

It extends all the way from the shadow part (on the left) to the highlights on the right.

With the default colors black and white and a Gradient Map Adjustment Layer is applied to this image then the black color will map to the left end of the histogram.

As we move through the histogram to the right the black will become lighter and lighter and eventually become white when it reaches the right side of the histogram.

What this gives is a nice smooth, rich monochrome image to admire.

This really is a simple procedure - it actually seems far too easy to do ...

Gradient Map Steps

Here's the picture that will be converted.  Before doing the conversion, the Levels were adjusted and the contrast increased with the Curves adjustment (Enhance > Adjust Color > Adjust Color Curves ...).

Now its time to add the Gradient Map Adjustment Layer - Layer > New Adjustment Layer > Gradient Map or just click on the little black and white circle in the layers palette and select Gradient Map.  

  1. Just to be safe make a copy of the Background layer and make your default colors black and white (Ctrl-X or Cmd-X).

  2. Select the top layer and make any adjustments you want to make - Levels or perhaps Curves.

  3. Add a Gradient Map Adjustment Layer above the top layer (Layer > New Adjustment Layer > Gradient Map ...).  

That's all there is to the conversion and now you've got a nice looking monochrome image. You can stop here or carry on with a few more steps to really make this great image pop (and truthfully this is where you're going to have lots of fun with the conversion).

There are, however, lots of different modifications and adjustments that can be done now that the image has been converted.

Post Conversion Modifications


When the Gradient Map Adjustment Layer is added this is the Adjustment panel for the new layer - there really isn't much to it, is there?

Putting a check mark in the Dither box will present any banding that may occur.

If your new black and white image looks like a negative then put a check mark in the Reverse box.

To make further adjustments to the gradient that has been applied just click on the gradient above the Dither box to go to the next screen.





Gradient Editor

This is the editor for the gradient and it provides lots of different options.  When you open the Gradient Editor you should see this screen - if you don't click on Reset Gradients.  For a true black to white image find the Foreground to Background gradient (the little black and white one on the left) and click it ...



Color Stops

The little things at each end of the visible gradient are called Color Stops (outlined in red).

When either of the Color Stops is clicked then the mid-point adjuster will be visible.  Grabbing the mid-point and moving it left or right will make some rather dramatic changes to your conversion.

Typically what I do is move the mid-point to the right because I'm partial to darker black and whites and the increase in contrast seems like a good idea (but that always depends on what you prefer and the nature of the image).  You can move the mid point around until you get the look you like.

Below the gradient is another section called Color Stops ...

Clicking on either of the left or right color stops will activate the little box at the bottom labeled "color".  Clicking on the little right facing arrow brings up three options (Foreground, Background or User).

When the solid color portion is clicked then the Color Picker comes up allowing you to change the color of the selected stop to anything you want - which brings up another topic and thats toning.Clicking on either of the left or right color stops will activate the little box at the bottom labeled "color".  Clicking on the little right facing arrow brings up three options (Foreground, Background or User).


When the solid color portion is clicked then the Color Picker comes up allowing you to change the color of the selected stop to anything you want - which brings up another topic and thats toning.

Toning

The power of the Gradient Map is that it maps any colors to the lightness values in the image.  Normally this will be from black to white but the two color can be anything you select.

With the left color stop selected and the color picker (AKA Select stop color dialogue) set as it is here then rather than having a nice black to white image the gradient will be from very dark blue to white - like this ...

Using blue rather than black and moving the mid-point slider to the left seems to give a richer look to the image (at least to me it seems that way).  The new color assigned to the left end stop can be a popular look like sepia or pretty much anything else you fancy.

For another take on toning thats different and very versatile check out Terry's Toning Tutorialusing Variations in Elements.

Special Effects

Once more back to the Gradient Editor.  Photoshop also includes a bunch of gradient presets (nine major categories) and any one of them can be selected to replace the one originally selected.

This is the default Presets setting and the others are ...

  • Color Harmonies 1
  • Color Harmonies 2
  • Metals
  • Noise Samples
  • Pastels
  • Simple
  • Special Effects
  • Spectrums

In total there are 91 different gradients available which should keep you busy for awhile just checking out how they all change your image.

Some of them have multiple stops which gives a whole lot of adjustments.

Here's one for example ...

This is fine and it can be improved with either a Levels or Curves adjustment.  

A contrast improving curve was added and here's the result - looks good!

That really has a Solarised look, doesn't it?

And here's the adjusted Curve for this image.


There you go - some cool things to do with a Gradient Map adjustment layer.  Find a nice image and do some converting!

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