Albino sauropods?

[andrewsaurus rex]

Interesting discussion here... I know I arrive a little late in it, but there is something I would like to add. Well, I will probably ram down an open door, but...

Have you noticed that among the modern large animals, bright colors are scarce? When we look at elephants, rhinoceroses, hippopotamuses, or even baleen whales, they all are in grey, drab brown or even black. Crocodiles are yellowish grey and even the "blue whale" is actually silver grey in color and is called "blue" because of the reflections of the sky on its skin. So, yes, it is rather reasonnable to imagine sauropods in greyish or brownish colors. In the modern world, indeed, the bright colors belong to smaller animals: birds, lizards, dart frogs, skunks (black and white is rather bright as a contrast); though leopards and tigers are big compared to us, they are way smaller than elephants and californian whales. See what I mean? So, yes, brownish-greyish sauropods is rather reasonnable as a concept.

Yes I have noticed that......for a long time now.  That's why I prefer dinosaurs in more sedate colours with perhaps a flash of colour around the eyes, nose or throat.  Colourful birds and reptiles tend to be small.  The bigger they get, the less colourful they tend to be.  Mammals are not a good guide, for the reasons stated above and it is often mammals that tend to form our opinions of how extinct animals should look and even behave.  While they may be a good guide for  extinct mammals, they're not for extinct animals that are not mammals.

But crocodiles, alligators, komodo dragons......I think they are a good guide and not only do they tend to be subdued/drab in colour, they all tend to be roughly the same colour.  Ostriches are not ambush predators and are not colorful, nor are emus.   Cassowaries are the most colourful, but just around the head region....

So it makes perfect sense to me to use this as a guide to dinosaur colouring.   On top of that, the little that is known about dinosaur colours has the bigger ones in a reddish brown.  The smaller ones feature bright colours. 

Unfortunately, just because it makes perfect sense, does not mean that is the way it was.  Nature constantly throws curve balls...

[Halichoeres]

For what it's worth, crocodiles also have poor color vision. Their cones aren't tuned quite to the same wavelengths as mammals' but they are dichromats, unlike other sauropsids.

[Newt]

We have a tendency to think of black as a concealment color like duns and grays, but it is not. Black is highly visible in most terrestrial environments and should be considered a display color. (Aside - this is why ninjas are extinct). Cassowaries, male ostriches, most species of bears, and so on are black because it shows them off, not because it conceals them.

Let's also not forget about the spectacular patterns that many large herding animals (giraffes, zebras, most antelopes, certain deer) show. Even if the purpose of these patterns is to confuse predators trying to pick out a single target (I'm not sure that's true but it is an often-mentioned hypothesis), these are examples of large animals with bold contrasting patterns, not overall drab color.

And finally, elephants show more color variation than we typically think of. Many Asiatic elephants in particular are black with rather bright pinkish mottling. This is often obscured by dust, but clean elephants can be quite colorful.