Render patch repair - colour matching

[greyam100]

Bon soir fellow experts and DIYers alike

Having trouble knowing how to get a similar colour to my patch repair.
Was thinking of a 5:1 sand/cement top coat but as seen in following photo my 4:1 repair to scratch coat is more of a sand/paisty brown shade rather than the lighter grey shade. Any tips on how to improve the colour to better match, appreciate it'll not be identical.

Do I need lime or white cement or dye?

 

[sxturbo]

I would advise playing around with different mixes add some stone and leave to dry and choose the mix that best matches.

Compared to your scratch coat it looks like it needs more cement to give the darker colour so maybe your right with the 5:1 mix, but mixing stones in it might change the shading.

 

[greyam100]

Thanks for your thoughts.

Per the photo:
The original scratch coat is a light grey colour
My scratch coat infill repair (bottom left of photo) is more a sand/brown shade, it was 4:1.
The top coat needs to be a weaker mix to minimise cracking, hence my reasoning for 5:1 but 5:1 would just be a browner colour than my already brownish 4:1 repair.

I'm thinking lime is involved so maybe 3:1:1 sand/lime/cement?

Or is there dye involved?

Cheers

 

[Alastairreid]

Durite Canterbury spar chips, 4-1 scratchcoat...5-1 top/ dashing coat.
Put waterproofer in the scratchcoat, plasticiser or a handful of lime on the dashing coat.
No dye.

 

[greyam100]

Thanks Alastair.
My 4-1 mix looks more brown than the grey req'd. 5-1 will be even more brown although nice and flexible. Are you suggesting the plasticiser (or lime) will affect the colour to match the existing grey? I must be missing summit here - have I got the wrong coloured sand (brown building sand), is it plastering sand or something else I need? Cheers

 

[Alastairreid]

Sand differs in colour depending what quarry the merchants source it from.
The lime helps to plasticise and make it more workable, the additive does the same.
For such a small patch it won't make much difference, its always going to be a patch you can only experiment with getting as close as colour match as you can. The more cement powder you use the lighter it will dry.