you are right especially about this particular photo.but sometimes,the menu is written in chalk to give the impression that these items are 'today's or chef specials'.a nice marketing ploy which suggests to the customers that they are buying something which is specially made for them that day.!Moshe's in mumbai tries that trick.actually,i think it was Moshe shek of moshe's who wrote an article about the tricks of the restaurant business(including fobbing off overpriced mineral water)
However, this does not rule out price rigidity.
When the chalk and board is replaced by digital pen and digital board, it indicates price volatility. (eg Petrol pumps)
This is thought provoking. Dont think Gokul restaurant will ever invest in Menu. However using chalk to write prices does suggest that, prices are changing very fast and its not economical to get new boards every few weeks.Frequent changes in any variable would indicate volatility but in prices should always indicate inflation.
Please note: Comments are moderated; I will delete comments that misbehave. The rules are as follows. Only civilised conversation is permitted on this blog. Criticising me is perfectly okay; uncivilised language is not. I delete any comment which is spam, has personal attacks against anyone, or uses foul language.