Mike,
Cannot disagree with that train of thought one bit, except, the photos need to be high quality for the instructions, kinda looks shoddy sticking photos of dirty/tarnished work in your instructions, well to my mind it does. Imagine opening up your £500 plus model and flicking through the instructions to find tardy, dirty and tarnished photos, not good cricket really.
As the instructions need to be built up as the model goes along you need to keep it clean at each stage, hence the multiple washing/cleaning. The other option....which I actually did on the GNR tender....is to fully build it and then primer it in grey. This worked very well as it's much easier to photograph the grey primer model than polished metal and much more detail can be seen. The only down side is that you have to then remember the build process and how to write it up at the end, not too bad for a tender but I'm already at four weeks on this chassis alone.
The trick I suppose is to take photos of each section as you go along, dirty and tarnished or whatever (place holders in reality), annotate and write up so you have a working product, then at the end primer it and go back and take the views again, this time with the nice clean painted model, insert into the instructions and all will be well.
If it were a build for myself then yup, it'd make no odds and one good clean or one or two during the build would be fine but for publications it has to be clean.
There's a couple of other options I'm looking at, a water softener which will help with the white blotches and residue once dried after washing with just hot water and mild detergent, also good for the rest of the house so the cost is justified; second, a bead blaster cabinet, that may remove some of the staining from the chemical cleaners.
I did try for an hour or so this evening to polish it with wire brushes in the Dremmel, the brass one didn't do a lot but the steel one did, quite well until suddenly for some unknown reason it just grabbed the metal overlay and effectively fluffed it up. Initially I though it might have got too hot or too much pressure, so letting it cool down (wasn't even mildly warm to begin with) I tried again, within seconds it started to grab the metal and distort it....hmmmph....it's kinda smoothed out now but is just another area to avoid in the photos.
Overall the exterior is nice and shiny, looks nice to, but it's still bloody brown tinted. Whatever chemical reaction has gone on is very deep in the metal, even really hard fibre brushes fail to lift it out. The end result is either more aggressive chemicals to try and restore the colour or simply less of them to begin with in the first place.
Ironically I've only got a handful of brackets and cylinder wrappers to fit and the chassis could go for primer almost right away.
MD