The standard does not differentiate between lighter or darker colouring of partridge. From the 2011 Bantam Standard, page 243:
"More attention should be given to the brightness and sharpness of the reddish bay ground color and the almost jet black penciling than whether the bird appears lighter or darker than an individual preference. The ideal is one uniform color over the entire body of the bird."
When Quoting the standard, it is better to put the entire statement not the part that you want. If you read the entire statement it is more clearer that it is in reference to a "normal" feather, not silkied. That being said, we as breeders know that when a feather is silkied, it does not follow the written ABA/APA standard exactly as written because of the change from a "normal" feather. Here is the entire statement from the ABA standard:
Color Of Female
Plumage
enciling in the partridge female should be of uniform width and conform to the shape of the feather. Each feather of the back,breast,body,wing bows and thighs should have three pencilings; the center black,then alternately reddish bay and black,ending with reddish bay edging around entire surface. More attention should be given to the brightness and ahrpness of the reddish bay ground color and the almost jet black penciling than whether the bird appears lighter or darker than an individual preference. The ideal is one uniform color over the entire body of the bird.
