Indicator paper issues!

After much more testing with the indicator paper - it seems that anything less than extremely acidic goes a bluey-grey colour with a purpley outline. Only the very acidic substances turn the paper pink,which is a shame, since some of the geothermal samples I've been given seem to be quite acidic (according to real pH paper and sample tests).

Nevertheless - an interesting range of colours coming up in the different portraits. Need to have reproductions of 6 decent ones, a statement and an application form done by Friday, so having a break from graphite portraits this week - sorry to those waiting for theirs to appear.

Adding indicator to samples directly - Whammy! COLOUR

LtoR: Tom Turner's Matarawa Stream (Whanganui) most alkaline. Natasha Petrove's Kakaho Stream, Distilled water (i.e pH neutral) , Rebecca Bennik's Oroua River (Manawatu), Nicole Bennik's Lake Horowhenua, (Levin), and Jessica Costall's Wai-o-tapu - geothermal stream (dissolved sulphuric acid? perhaps causing the strong acidic reaction here)

From this it's clear that the indicator paper is not nearly as sensitive as the raw indicator dye - not sure how to combat this. Am actively seeking pH neutral paper, having discovered that the latest batch of 'acid free' paper I bought is much more alkaline than the last (I know because the paper turned greenish before I even put anything else on it.)

Having said that, as Hannah so kindly pointed out, it's an exciting day - I will have to see just how long the colour lasts, because as they are in this photo - there's a huge colour disparity between samples; this might make an interesting comparison with the samples in their natural state, or even just an artwork by itself.

Am also still looking for an appropriate box for a glass sample jar to be displayed in.
There's a nifty explanation of using redcabbage indicator here, which also has a sweet picture of the range of results. 

Water Portrait Trials