Photos: How to Create a Sepia Tone Effect

iPhoto and Aperture had the nice Sepia Tone effect to create sepia toned Black and White photos. This effect is missing from Photos.

It can be recreated in Photos using a combination of the adjustments "Color > Saturation" and "Curves". By looking at the colors of a sepia tone image, we can see that the red channel is the brightest, and the green values are roughly 98% of the red values. The blue channel is much darker, only 80% of the red channel. To set this color balance do the following:

• First, remove the saturation completely, by dragging the saturation slider in the Color adjustment section all the way to the left to -1.0. If you leave a little saturation, -0.8 or so, you will create the "Antique" effect instead.
  
• Now click the disclosure triangle to the left of "Curves".
  • Leave the Red curve as it ist.
  • Set the selector to "Green" and grab the upper right corner of the Green curve and lower it just a little bit, by 2% or so. Be careful, that the curve stays a straight line. The curves tend to wiggle like snakes, if we move the pointer along the curve and not just drag the endpoint down. If you accidentally create a new definition curve on the curve, drag this new point towards the endpoint. The green curve should look like this:
    
    
  • Set the selector to "Blue" and grab the upper right corner of the Blue curve and lower it by 20% or so.
    The Blue curve should look like this:
    

Now you can copy the new Sepia adjustment from the photo where you applied it to other photos. While in Edit mode, use the Image menu: "Image > Copy adjustment ⇧⌘C" to let the adjustment from the selected image and and "Image > Paste adjustment ⇧⌘V" to stamp it onto another selected image. If you apply the keyword "Sepia" to your Sepia Photos, you can quickly find back to a photo, where you can lift and stamp the adjustment from. Or create an album with sample adjustments.

With the saturation slider set at -50% the photo will have faintly saturated colors like in the iPhoto Antique effect:

Added: To recreate Aperture's Cyanotype:

For the black end of the curves, for the dark shadows, raise the blue and the red curve slightly, so even the darkest shadows will have a dark, purple tint.

For example:

The Sepia filter is primarily changing the color of the bright image areas, the Cyanotype effect does not tint the bright areas so strongly, but is changing the colors of shadows more. So I moved the green curve slightly away from the black point - the shadows are now strongly purple, while the highlights are still white or of a neutral gray.