Sorry about the horrid Flickr file names. Flickr generates arbitrary file names for downloaded images. I should have linked the images to either Exploratorium files or the NASA MER site files. Both of them use names with the filter information coded into the image filename.
To share a Flickr file you have to copy the code in the "Share" pulldown button that is on the top left of the picture.
First, click on the "Share" button, then click on the "Grab the HTML/BBCode triangle, then select a convenient size ( I use Medium 500 a lot ), then select HTML for this blog and then select the code ( a single click on the code will select all of the code ) and then copy it ( ctl-c ) and then, finally, paste it ( ctl-v ) in the comment filed of this blog.
Er, the pancams have no Red, Green or Blue filters. What they have is a dog's breakfast of mostly narrow band filters named 1...8. The filters for the left and right pancams are, of course, different. Each filter is explained in this document in the section for character 25 ( Camera Filter ) of the Filename.
The filter map:
( R, G, B ) = ( L4, L5, L6 )
is the closest match to a "real" natural color - with some footnotes.
There are literally dozens of color maps that are commonly used.
Perhaps the most common is the "false color" map of:
( R, G, B ) = ( L2, L5, L7 )
Notice that the sundial color chips look quite different in "false color".
The companion right eye map is the synthetic color map:
( R, G, B ) = ( R3, avg(R1,R2), R1 ) -
with a hue shift. ( don't ask. )
or perhaps something more complicated, like my favorite:
( R, G, B ) = ( max( R3,R4,R5,R6,R7), avg( R1,R2), R1 )
( avg is the average image of two different images. )
Perhaps the most unusual is the "sunset" map:
( R, G, B ) = ( R4, avg( L7,R4), L7 )
In fact, some very strange combinations are used routinely:
( R, G, B ) = ( L2, avg(L2,L6), min(L6, L7))
is used for the miniTES calibration target.
In fact you can be creative and combine the filters any way you want to highlight certain minerals. Winston has played with Ratio color to highlight hematite signatures in the images.
Perhaps now is a good time to stop the lesson and wait for the "aha" moment from the students.