is it the crystal or dial

[jackteet]

Hi, I am new to the world of vintage watches and thus far have near mint Gruen veri-thin, waltham and an Elgin. A Bulova senator is on its way to me from the US which I purchased from ebay. US. This again is in near mint and the purchase price was really silly.

Anyway my problem is with my 1950`s Elgin. In daylight there is a blue/grey tint when looking at the dial. In sunlight that tint turns  yellowish. I assumed it to be patina but I took a pic of the dial with my phone and to my surprise the pic shows a mint clear dial. I have searched the internet and watch forums for an answer and it appears that patina would show up on a pic but it is likely the crystal has deteriorated over the years and has  discoloured. 

May I ask for opinions please before I visit my friendly watchmaker. I havent attached a pic as there is nothing adverse to see. TIA jack 

[jdm]

Just look at the dial with the mov.t outside the case. Normally that is very easy and does not require a watchmaker, there maybe exceptions depending on the case construction. 

Also, when asking questions please always post clear pictures to help others help you. 

[jackteet]

Hi jdm,I didnt post a pic cos there is nothing to see other than nice clean mint dial A tint/disclouration is not visible so a pic will not help.

I do not have the expertise to strip anything otherwise I would have done so. I can clean and polish and thats it.

I have detailed the info concerning the colour of the dial  and would appreciate knowing whether a discoloured crystal is possibly the cause. thanks jack

[LittleWatchShop]

1 hour ago, jackteet said:

discoloured crystal is possibly the cause

yes it is possibly the cause