Do you plan to keep this project for more than a few weeks? If not, then use a DVD-RW and erase it when finished.
NOTE: DVD+RW consistently prove themselves as an unreliable format (in terms of longevity) in our tests, so DVD-RW is always suggested. If the machine ONLY works with DVD+R or DVD+RW, then buy DVD+R and throw them away when finished.
DVD-RW and DVD+RW do not use dyes, these use a malleable "phase change material" that can be altered. It's not meant for permanent storage, not at all.
If you want to keep these photos, keep this project, then by all means, use a permanent dye-based media, such as DVD-R or DVD+R. If this is going to be an archive, then burn the project several times, to several different known-quality discs. And I mean different as in "different brands". For example:
- Taiyo Yuden DVD-R
- Taiyo Yuden DVD-R
- Verbatim DVD-R
- Verbatim DVD+R
- Sony DVD+R
If this needs to be "safely stored" then don't just burn it once. Go one further by burning the discs several times over and storing several copies in several locations (not one disc per site, but minimum 2-3 discs per site), such as an office or home of a parent/relative.
Rewritable discs are also more expensive, and it's not economically smart if these are being duplicated and distributed to the audience. For distribution, you can get Verbatim and Taiyo Yuden media for a good price, and it's worth using these discs. Bad discs to your audience members does not yield positive results.
A list of the best discs, and where to buy them, is here:
http://www.digitalfaq.com/media/dvdmedia.htm
Hopefully that answered your question -- and then some.