Lightest grey text without a penalty?

[Tonearm]

Can anyone tell me what is the lightest gray text color I can use on a white background and not be at risk for a Google penalty?

[phranque]

if it's not readable in a manual check then you are at risk.
i would say it should be dark enough to be read by someone with eyes that are fatigued from reviewing spammy sites all day.

[chalkywhite]

Subtle phranque ;)

[rish3]

Google filed a patent on detecting hidden links: [patft.uspto.gov...]

The part that might be relevant for you:

If two colors are not the same...[the algorithm] may determine that the two colors are similar if they are within a configurable range, or a predetermined range, etc. For example, when the colors are represented as color values, server 120 may determine that two colors are similar if their color values are within 50 (or some other value) levels of color of each other.

I assume "50" wasn't completely arbitrary, though it does say "or some other value". I'm also assuming they mean the sum of the difference across the R, G, and B spaces. Some other context I didn't quote implies that the 50 is a base 10, not hex.

You mentioned grey on white, so if it's truly a white background (#ffffff), the minimum grey would be #eeeeee. Personally, that still looks too subtle to me. The color #dddddd on white is clearly readable to me. That represents a decimal difference of 34 for each of R,G, and B, for a total difference of 102. That's twice the example cited in the patent, so I'm assuming it's safe.

[phranque]

actually the minimum grey would be #FEFEFE

#EEEEEE would be a difference of 51 total, so if you're feeling lucky...

[rish3]

actually the minimum grey would be #FEFEFE

Well, I meant the minimum grey to achieve the difference of 50 decimal and still be "grey".

#EEEEEE would be a difference of 51 total, so if you're feeling lucky...

Hence why I called it the "minimum grey"

[phranque]

sorry i misunderstood.
good find of that patent, btw!

[Tonearm]

Killer analysis guys. Thank you.

[Tonearm]

Does changing the font-color of default black text on a #ffffff background to #dddddd de-emphasize the text for Google?

[rish3]

Does changing the font-color of default black text on a #ffffff background to #dddddd de-emphasize the text for Google?

I'm guessing, of course, but I don't think color implies emphasis in any fashion. Just a boolean of "hidden" or "not hidden". Emphasis would be via markup (h1, h2, b, ul, strong, etc).

[levo]

On Adsense ad unit settings, anything lighter than #BFBFBF reverts to #828282

[lucy24]

I don't think color implies emphasis in any fashion

I'd be disappointed in google if after all this time they can't tell when {color} and {background-color} are the same-- even if they happen to come in entirely different areas, like

<div class = "meaningless-name">
{lots-of-other-stuff-here-to-lull-algorithm-into-false-sense-of-security}
<p class = "super-important-text">
Words-I-couldn't-fit-into-the-page-any-other-way</p>

corresponding to
div.meaningless-name {background-color: #777;}
and
p.super-important-text {color: #777;}

Within the same declaration it's trivial. Even the css validator flags those.