Find out what was revealed when two of the Walker's portraits by Joseph Wright of Derby were conserved in our conservation studio. David Crombie explains: "When these of portraits of Fleetwood Hesketh and his wife Frances Hesketh were hanging in the gallery, they appeared to be in good condition, apart from their slightly discoloured varnish. However, nobody expected how discoloured the varnish and dirt layers would turn out to be. Once the varnish and dirt were removed, we could see the bold areas of colour and Wright's distinct subtle purples that were somewhat obscured until now. It's remarkable just how bright the paintings really are. The yellowing of the varnish is a result of the gradual oxidation and degradation of natural resin varnishes over time. Underneath, the original paint is generally in very good condition and these portraits are good examples of a sound oil painting technique. Wright painted them in a very consistent manner and didn't use any particularly radical techniques, unlike Sir Joshua Reynolds for example, who could be more experimental. One interesting thing that we noticed in another portrait being lent to the exhibition from a local collection is that the lady in the painting appears to be wearing a similar blue material wrap and wristband to the ones worn by Frances Hesketh in the Walker's portrait. The wrap is even tied in a similar way at the front. This may mean that they were studio props given to sitters by Wright. However, we'll have to check to confirm this when the loan painting comes in and we can examine them properly together."