Idiot question #6 - why is colour film denser?

[VirtualAdept]

Ive just finished deving two rolls in caffenol, a roll of ilford something or other (400 iso) and a fuji colour film (also 400 iso).
Now, since they're the same iso I decided to dev them together, figuring 400 is 400 is 400, so why are the colour negs seemingly so much denser than the b&w?
Can I safely conclude from this that, since they were both shot in very similar conditions, the colour film requires more developing?

 

[freecom2]

It could be the lack of a bleach step that colour film normally goes through with C41 process.

 

[mustanir]

C41 film has three layers of silver.

The bleach removes all the silver and leaves behind just the colour dyes in conventional c41 dev, there won't be much in the way of colour dyes if devved in caffeinol, so no need for bleach.

 

[VirtualAdept]

Right, that makes sense... thanks guys

 

[freecom2]

C41 film has three layers of silver.

The bleach removes all the silver and leaves behind just the colour dyes in conventional c41 dev, there won't be much in the way of colour dyes if devved in caffeinol, so no need for bleach.

Prepared to be proven wrong - thanks for the correction, I need to read up more.