If you are suggesting chromogenic prints here, I can't imagine they will look anything like cyanotypes even if the scanned original prints were contact prints using cyanotype.
Originally Posted by David William White
If a digital step is to be involved, I suggest the OP visit hybridphoto.com and investigate how to make proper digital negatives that will match the scale of the cyanotype emulsion. There are a lot of friendly people over there willing to offer good advice. Check out posts made by user mkochsch on using HSL arrays in particular. (OTOH, a film scan could also be taken into Photoshop, desaturated and then colorized blue and printed out via inkjet to a rough paper to mimic the cyanotype process better than a slick surfaced RC chromogenic print.)
If it is important to match the older cyanotypes, I say give them give them real cyanotype prints.
Cyanotypes may not be archival, but I have one that's still very blue after more than 120 years! From the buildings in the picture the negative must have been exposed before 1870, so I assume the print was made not too many years later.
Different papers behave differently in different toners. Ilford MG IV RC hardly reacts to anything, and Bergger Art Contact reacts extremely quickly and goes violently blue within seconds - in old weak toner that doesn't affect other papers at all.
Somewhere between those two extremes you should be able to find a paper that gives nice, controllable tones.
Cyanotypes are only not archival if they've not been washed properly so the excess unreacted chemicals come out (eg no more yellow in the highlights). Cyanotypes are also unusual in that they like acidic enviroments so "archival" papers with buffers and stuff are actually bad for cyanotypes and will make them fade/bleach. I think blue-toned silver gelatin prints are NOT archival because the iron in them reacts with the silver which causes it to degrade... at least that's my understanding.
I've found cyanotypes extremely easy to work with and if you're in the US, you don't realise just how lucky you are to have cheap large format lith film available from places like freestylephoto. I'm seriously considering importing some 8x10 lith film from them because even though it'd cost me 60orso UKpounds (the shipping and VAT and duty approximate), that's still cheaper than lith film here (for a hundred sheets) and not much more than cheap fomapan panchromatic film which is what I'm currently using for enlarged negatives for 35mm to 4x5inch film. The chemicals I bought back in April last year are still going, it cost me maybe 13ukpounds for them. I've found loads of different cheap papers that work happily with cyanotype so you don't have to go with the expensive arches aquaelle or cranes papers. Ortholith film is the way to go if you're scared of working in complete darkness and can get the film at a reasonable price because then it's no different than working with paper from what I've heard... you even use paper developer to get pictorial contrast.
Oh yeah and the light box? Don't bother building your own if you're doing about 8x10 size, just get a facial tanner, those things can be had for less money than buying the bulbs.
There was a recent thread about blue toning - you may wish to read through for ideas:
I reckon this link will provide a closer cyanotype look. It's on the Moersch site, unfortunately there's no direct link:
Click on the gallery and then look for MT7 Eisenblautoner
Also click on Tutorial as there are some cyanotype images of a rather fine looking model.