Underexposed. Increase or decrease development time to compensate

[OptiKen]

I started playing around with a Maximar 207/7 and Arista Ortho II film.
I exposed the film at ISO 6 and after developing the first sheet, I can see that it should have been at ISO 3 instead.
I have 6 more shots exposed with the same settings and I would like your input on how to compensate for the under exposure.

Should I increase or decrease developing time to compensate?

Thanks in advance

Ken

 

[crumpet8]

You want to push process or "over develop" your film if underexposed. Unfortunately I can't give you further details as I'm not familiar with those you're working with. There is usually good information regarding processing on the product sheets