Comments on: Using Photoshop’s Calculations tool for black and white conversion

By: Paul Sophocleous

Paul Sophocleous — Thu, 01 Dec 2016 09:08:25 +0000

This technique does not create a black and white image, it creates a selection. If you look in your channels palette, you will see it as Alpha 1. When you look at the black and white image, you are looking at just the individual channel, not the RGB image.

To create a black and white image that you can save, create a new layer at the top of your layer stack, and fill it with black. The go to the Select menu, choose load selection, and choose Alpha 1 (or whatever your alpha channel is called. With the selection active, fill it with white. Now you have a layer that has your black and white image on it.

By: mike

mike — Wed, 28 Oct 2015 23:39:51 +0000

same trouble here - how to save it? The background is still in colour

By: shelly

shelly — Sat, 28 Jun 2014 17:05:38 +0000

How to save it... When I save the image I got the same pic not b&w

By: ElendilTheTall

ElendilTheTall — Sun, 16 Sep 2012 17:40:37 +0000

The two channels are blended in the same way as they would be if you manually stripped them out of the image, placed them as two layers, and set the blending mode of the top layer accordingly. I believe the third channel is discarded.

I have no idea how it compares to Lightroom's tools as I have never used Lightroom, but I imagine they are similar to Photoshop's Black & White adjustment. They offer a very flexible approach and there's nothing wrong with them by any means - Calculations is just another, perhaps quicker, way to go about conversion.

By: francesco

francesco — Sun, 16 Sep 2012 06:40:00 +0000

I didn't know this tool. How are the two channels combined? What happens to the third channel? And finally: how does it compare with LR tools, is there some equivalent way, since in LR black-and-white conversion offers many slider for each colour?