The "Light" Coloration

you're right. S/S and Co/Co make a silver columbian
it doesn't have to be duckwing (e+) based though
see the chicken calculator
http://edelras.nl/Henk69/kruising.html
Walt

the "Light" phenotype is based on eb/eb S/S Co/Co

I bow to your greater experience and expertise nicalandia,
out of curiosity, though, how does it look different with e+ or E^Wh?
Walt

If the males of the variety have saddle stippling, then they are eb based. If not, they are eWh based.

that is not necesarily true, exhibition wheaton does not have hackle striping however many wheatons will and do develop the hackle striping, these wheatons are very usefull in conjunction with with Columbian.
If gresh is discussing the Columbian color pattern and is looking to introduce it to his oriental game which are often wheaton based but have some hackle striping it is quite simple.
here is a silver patterened columbian OE game that has considerable wheaton influence, and has good striping to hackle and saddle.


wheaton is very usefull with columbian to keep the pullets and hens backs cleaner you just have to select for slighty lighter under down, and good hackle striping.

when I first posted I was thinking about Silver Columbian(Columbian Wyandotte) instead of the "Light Coloration" found on Light Sussex.

indeed, the "Light" Coloration is based on eWh/eWh S/S Co/Co as found on the Light Sussex.. the Silver Columbian genotype is based on eb/eb S/S Co/Co
I don't know how e+/e+ S/S Co/Co looks, I have yet to see a bird like that. I would guess the stippling could be like eb/eb?

as Sjarvis stated this is almost 90% of the case, but you can say eb/eb will had a lot more stippling that eWh /eWh could. some eWh/eb heterozygotes could show stippling on males..

below is a side by side of eb/eb S/S Co/Co(Wyandotte roo on the left) and eWh/eWh S/S Co/Co(Light Sussex on the right) you can clearly see how eb/eb adds stippling on the rooster saddle

It doesn't have to be Partridge based. It can be duckwing or wheaten, too.

Your best colored Columbian patterned birds that are easily single mated are wheaton based, This allows for very well colored male and female birds that keep clean un-stippled primaries often through-out thier life, as well as improved wing primary edging of white in both sexes and decreased white spots in black areas of the wing primaries, secondaries as well as good lacing on black tail coverts, improved black on tail primaries and decreased white on sickles of males.

The duckwing base brings in more stippling not always seen in the first adult feather but often in later molts leading to more of a dirty body plumage in both sexes.

The Partridge base in order to breed for best color you almost have to double mate for your male line with good hackle and saddle color you will need "dirty" backed females this is critical for keeping the saddle striping strong, for your female line you want males that are very weak if not absent saddle striping to keep the females backs clean.

this can be a tricky color to breed exhibition quality in pattern.

Here's an interesting study.

Best,

Karen in western PA, USA

"The pigment cell system in the Light Sussex fowl."
 By J COHEN

Article in Publication: Journal of embryology and experimental morphology, 1959 Sep; 7: 361-74

 Database: From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
ISBN/ISSN: 0950-1991 . "Summary" and the paragraph directly above it sum it up very well.
Fascinating. It seems this study reveals that each feathers' color isn't programmed
individually, but by how each feather interacts with the epidermis .

Find it at: http://tinyurl.com/ygrb7bb (just click on the "download button" .)