Do you need a pure white base to go for silver?

For silver you need a very pale base to tone to achieve the colour.  Gold isn't going to cut it I'm afraid.  It also depends on which shade of grey/silver you want,  the darkest available that I have tried is Nirvel Art X, and that is quite dark and purply neat,  which would probably be the only way you could use it at this point.  It is possibly  too dark for what you want  currently, and I'm not sure it would cover the colour you have at the moment.

Do you have some reference pictures as to what you're after? I have attached a picture of my hair dyed with Pravana Silver, it looks pretty even in the picture but there were lots of greeny muddy fade areas where my hair was too yellow and it was starting to show. I would call this a mid to dark grey. 

Another option is to dye the lighter areas grey/silver and put purple or blue over the more yellow areas to cover them until you can safely process again. I always do this when I don't get my roots light enough, there is an example of this here : http://www.hairdyeforum.com/index.php?topic=11521.0

For silver you need a very pale base to tone to achieve the colour.  Gold isn't going to cut it I'm afraid.  It also depends on which shade of grey/silver you want,  the darkest available that I have tried is Nirvel Art X, and that is quite dark and purply neat,  which would probably be the only way you could use it at this point.  It is possibly  too dark for what you want  currently, and I'm not sure it would cover the colour you have at the moment.

Do you have some reference pictures as to what you're after? I have attached a picture of my hair dyed with Pravana Silver, it looks pretty even in the picture but there were lots of greeny muddy fade areas where my hair was too yellow and it was starting to show. I would call this a mid to dark grey. 

Another option is to dye the lighter areas grey/silver and put purple or blue over the more yellow areas to cover them until you can safely process again. I always do this when I don't get my roots light enough, there is an example of this here : http://www.hairdyeforum.com/index.php?topic=11521.0

Thank you for the reply, I thought as much but just wanted to check first! Very helpful 🙂

I love love LOVE the photos of your hair in the other thread, the purple at the roots with the silver just looks so amazing! How did you manage to blend it so well? I would just end up with a blunt line where the purple ended and silver began lol but it does look stunning and you've certainly inspired me!

I won't be processing for a while, I did my roots on Friday just gone so will wait my usual 6-8 weeks before doing roots and bleach-bathing the darker bits. You've certainly given me food for thought.

No worries, it can be hard to achieve, and my hair is very resistant to doing so. I never aim for white, just the palest blonde I can achieve, then I tone with silver shampoo before dyeing.

Thank you, I just applied the silver first and added the purple afterwards.  Then I blended them together in the middle.  I just sort of rub it around, but I have been doing it for a long time,  there are some threads around with far less vague/way more helpful instructions.  🙂