RE: No description for image/tiff in Impl-Guide

> Tamura-san,
>
> Some related edits could be:
>
>   5.4 Content-Type for the file format
>
>   The content-type "image/tiff" should only be used for Profiles S and F.
>   Some existing implementations based on [RFC 2301] may use "image/tiff"
for
>   other Profiles.
>   However, this usage is now deprecated.   Instead, the content-type
>   "image/tiff-fx" whose
>   registratin is being defined in [TIFF-FX-REG} should be used.
>   Also, "image/tiff-fx" may be used for Profile S and F.
>
> BTW, is the last sentence true, or would image/tiff always be used
> for S and F?

If you you're only sending Profile S or F, I don't see a need to "scare"
a receiver into thinking you're sending a higher-complexity TIFF.

So, I would recommend striking the last sentence above and replacing it
with:

  To achieve the highest amount of interworking with devices only
  capable of rendering Profile S or F, "image/tiff-fx" SHOULD NOT
  be used for Profile S or F; rather, "image/tiff" SHOULD be used.


Note that in IETF standards language, implementations can ignore
"SHOULD" requirements if they desire.

-d