Warning: Way too much information coming. This will only be of interest to people who want to pay for really good paper. My understanding of paper is not through technical education and I stand ready to be corrected in detail by others who have a greater knowledge of modern papermaking. I am a working artist with a passion for the stuff and an occasional excess of opinion.
Bristol can be bought with a "plate" finish for pen and ink or technical drawing or a "kid" finish for pencil. What makes it Bristol is the hard sizing as well as the finish - at least traditionally. Hot press printmaking and hot press watercolor paper have a very similar surface look and feel but they are sized differently from Bristol.
Strathmore Bristol appears to be hot press and compares with other hot press papers I have tested. Their watercolor appears to be cold press and as such appears to compare with other cold press papers.
Strathmore has made cold press, hot press, rough, laid, machine mold and maybe even mold-made paper over the years (here memory fails) for various markets. The amount and quality of rag in the paper is important as is the quality of the sulfite pulp used (if any) and the presence of other materials. Bleaching is a factor as is the presence of optical whiteners, which have been added to the mix in recent years.
Most machine-made papers do not have a face side and a screen side unless this is engineered into the product to give an artist a choice, since most finishing is done between rollers. The cold press paper used by PhotoEngineer may be so designed. Traditional, mold-made paper, identifiable by 4 deckle edges, is dried stacked in 100 sheet piles (posts) or it is dried in contact with a plate, cold or hot. Laid paper, often used today for expensive stationary and charcoal drawing, has a distinct pattern of a makers frame crossed by thin brass rods laid in a row, with heavier rods beneath them, rather than screening, which is a relatively recent invention in the world of papermaking.
As may be evident in this rant, I'm somewhat... enthusiastic about paper. I used to do a lot of intaglio printmaking and the qualities of the paper I used controlled the experience of the process. I am a relative beginner to serious photography and tend to use the commercially available photo papers - even RC for much of my quick work. In hand making what we hope to be archival photographs however, I can't believe that the quality of the paper we use could be less important than the chemicals or the technique. We have paper being made for artists today the same way and in some cases the same shops as it was made over 400 years ago for the simple reason that some of the paper made then is still around in museums, having stood centuries of storage and hard use. Poorly chosen paper may not show its shortcomings until the piece is framed and on the wall, but it will usually fail you in some way.
Bottom Line? Ask a knowledgable paper seller about the proper weight, finish and sizing for the processes you will using (coating, brushing, soaking, inking, etc.) Don't pick a paper because it feels smooth and heavyweight.
There are artisan papermakers all over America and Europe and a lot of information is out there. [end rant]
To answer about the single ply that I use and the pads, they are different.
I have never used the pads. I don't use 2 ply because it doesn't stand up well to extended immersion.
SInce the sheet with the problem was the top sheet, it most likely was made unuseable prior toyou purchasing it. The oil from peoples hands will cause the paper to not take the sensitizing solution evenly. I teach my students to never touch the paper in the image area in order to eliminate this problem.
[FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]
I use Strathmore Bristol smooth in cut sheets in pads. It is 100# weight.
It holds up well to immersion in processing solutions and during washing for extended times.
The other papers that I routinely used at EK were made in our own plant and had a wire and face side, and were hot presssed with heavy calendaring rollers. I knew a bit about them, but I have no information on the Strathmore products. All I can say is that I have used all available types and they work. So do the Cranes and Lanaquarelle and Bergger COT320. The difference is mainly price, and the fact that the cold press are slightly less satisfactory in some cases with silver halide in gelatin if they have a textured surface.