I wanted a quick way to get an Autochrome-like look to some images. My preferred method is to use a Lightroom preset as a starting point but I couldn’t find a downloadable preset that gave me the look I wanted. However Mark Abeln over at The Refracted Light did some interesting work analysing the colour gamut of autochromes. Using this as a basis I made my own preset. Although Lightroom Develop adjustments don’t allow an exact replication of the gamut, it’s the effect I’m after, not scientific accuracy. Apart from the colours, Autochromes are noticeably grainy. The Lightroom control for this will need adjusting depending on the resolution of your original and the size of your reproduction. You can download my preset from my Web site. Unzip the file autochrome.lrtemplate and save it to (on Windows) [username]/AppData/roaming/adobe/lightroom/develop presets/user presets/
Before applying the Autochrome Preset. © Malcolm Raggett
After applying the Autochrome Preset. © Malcolm Raggett
Mal Raggett's Photo Blog 
Thank you for this template.
I actually tryed to use for a shooting i did during a short reconstitution of the first world war (people in costumes in a cave, in a field…).
To my mind this is a little to grainy for a portrait, but it’s easy to play with the settings and way easyer than the photoshop tutoriels i found.. even though i’d like to try and see the results whith photoshop…
ps: sorry for the mistakes, english is not my native language.