Converting an image to grayscale and back to color is a common image editing technique in Adobe Photoshop. Grayscale images contain only shades of gray, while full color images contain a range of colors determined by the color mode (RGB, CMYK, etc.).
Going from color to grayscale removes the color information from an image, but preserves the luminance or brightness levels. This can help simplify an image or draw focus to patterns, shapes and textures rather than color. Converting back to color then re-introduces color information to the grayscale image.
Photoshop provides a couple straightforward ways to convert between color and grayscale, giving photographers, designers and other creative professionals flexibility when editing their images. In this guide, we’ll cover the step-by-step instructions for converting to grayscale and back to color in Photoshop.
Converting an Image to Grayscale in Photoshop
Photoshop has two main options for converting an image to grayscale:
1. Image > Mode > Grayscale
This menu option converts the image’s color mode to straight grayscale across all layers:
– Open the image you want to convert in Photoshop.
– Go to Image > Mode > Grayscale.
– In the dialog box, click “Discard” to discard color information, or click “Keep” to preserve the color layers. Usually you’ll want to discard color when converting specifically to grayscale.
– The image now appears in grayscale only.
2. Black & White Adjustment Layer
Instead of changing the overall image mode, you can add a Black & White adjustment layer to apply grayscale to just that layer:
– Open the image and add a new layer if you want to keep the original color version intact on its own layer.
– Go to Layer > New Adjustment Layer > Black & White.
– This adds a Black & White layer that automatically converts the layers below to grayscale.
– You can adjust the intensity of various color ranges by moving the color sliders.
The Black & White adjustment layer gives you more control over the conversion than changing image mode directly.
Converting Grayscale Back to Color in Photoshop
Once you’ve edited the grayscale image, you can convert it back to color in Photoshop as well. The process depends on how you initially converted to grayscale:
Grayscale Image Mode
If you used Image > Mode > Grayscale to convert to grayscale directly, do the following to convert back to color:
– Go to Image > Mode > RGB Color or CMYK Color to change back to your desired color space.
– In the dialog box, click “Keep” to preserve the grayscale tonal information. Selecting “Discard” would make the image appear flat and monotone.
– Go to Image > Adjustments > Hue/Saturation and adjust the controls to introduce color tinting.
Since the original color information is gone, you’ll need to re-introduce color manually using Hue/Saturation. The grayscale tones will become your color luminance levels.
Black & White Adjustment Layer
If you used a Black & White adjustment layer, do the following:
– Turn off visibility for the Black & White layer by clicking the eye icon to show the color version underneath.
– You can keep tweaking the slider controls on the Black & White layer to selectively convert parts of the image back to color underneath.
– To completely remove the grayscale effect, simply delete the Black & White adjustment layer.
The color information remains intact on layers below the Black & White adjustment layer. So you have full access to the original colors just by removing the adjustment layer.
When to Convert Images to Grayscale in Photoshop
Here are some common reasons you may want to convert images to grayscale:
– Simplify the image by removing distracting colors. This draws more attention to forms, shapes and textures.
– Make color differences less pronounced between objects. Help direct focus without color dominance.
– Prepare an image for conversion to duotone or monotone effects by starting with a grayscale version. Add tinting selectively.
– Establish strong contrasts between light and dark areas in black & white photography.
– Provide color consistency with a group of varied images by converting the set to a common graytone appearance.
– Add an understated or classic look associated with grayscale photography. Works well for certain moods or aesthetics.
– Create more emphasis on light and shadows, high/low key effects, silhouettes and contours.
– Facilitate conversion to line art or pen and ink style illustrations by starting from grayscale.
Tips for Converting Images to Grayscale
Here are some additional tips for converting images to grayscale effectively:
– Be mindful of any loss of detail when discarding color information. Keep layers separate if needed.
– Avoid extreme brightness adjustments after converting to maintain tonal separation.
– Use adjustment layers instead of direct mode change for more control over grayscale mix.
– Add a Color Lookup adjustment layer after converting to grayscale to tint with monotone hues like sepia.
– Use the targeted HSL sliders in the Black & White adjustment layer to control conversion of specific color ranges.
– To accentuate details, try applying mild Sharpen or Clarity filtering after the grayscale conversion.
– Use Curves or Levels adjustments to extend dynamic range from shadows to highlights of grayscale image.
– Apply masking techniques to selectively hide or reveal color behind a grayscale adjustment layer.
– Use layer blend modes like Overlay to blend grayscale and color versions together.
Achieving Optimal Grayscale Conversions
Converting images to grayscale while retaining important detail requires an understanding of how Photoshop calculates luminance. Here are some keys for success:
RGB vs. Luminance Values
Photoshop bases its grayscale conversion on the luminosity or luminance values of colors. This differs from straight desaturation of RGB channels:
|255, 0, 0
|0, 255, 0
|0, 0, 255
As seen above, green has much higher luminance compared to red and blue. So although RGB values decrease evenly in desaturation, luminosity matches human perception of brightness.
Edit Masked Areas Separately
Applying grayscale universally across an image won’t always yield great results. Often you’ll want to control the conversion more selectively.
Use layer masks and selection tools to isolate areas and apply grayscale only where needed. Adjust luminance, contrast and blending separately for the best outcome.
Skin tones are a good example, requiring more reddish luminance values compared to the greens of landscapes. Target each area as needed.
Preserve Details with Blend Modes
Grayscale can reduce apparent details, especially in shadows. Using blend modes like Luminosity can help retain detail from the color image.
Convert to grayscale on one layer, then change the blend mode to Luminosity. This combines the color detail and grayscale tones for a more defined result.
Converting images to grayscale and color in Photoshop just takes a few steps, but mastering the most realistic and visually pleasing effects requires some practice. Take time to work with the different methods and adjustment tools.
Pay special attention to luminance values, tonal separation, preserved details and selective masking. With experience, you’ll be able to adeptly handle any type of photo and conversion challenge.
Hopefully this overview gives you a good starting point for grayscale conversions. Apply these techniques to your own images and see what dramatic effects you can achieve in black, white and color.