Hi Luke,

Thank you for contacting Mearto with your appraisal inquiry.
Several of Namatjira's watercolor landscapes of similar size and composition have brought between AUD$30,000-40,000 at auction but yours has some condition issues - brown spots (toning and foxing) - that decrease it's value. Also, the value assumes that this is an original work on paper and not a print reproduction (if that's the case, this would have a value of AUD$500-800).
Based on the photos and information provided, and subject to examination, this is:

Albert Namatjira (Australian, 1902-1959)
Untitled (mountain landscape with gum tree in the foreground)
watercolor on paper
matted and framed
signed lower right, above the mat line
350mm by 500mm (13 3/4 by 19 5/8 inches)
CONDITION: with toning and foxing
PROVENANCE: inherited
AUD $20,000-30,000*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you again for using Mearto.