What food colouring for rainbow cake?

[iwasagirlinavillage]

What food colourings should I use to keep a really vibrant colour in the sponge? DD wants a rainbow cake for her birthday and I've never successfully kept the colour after baking.

I ordered these from Amazon the other day and they're very vibrant; a little bit really goes a long way.
PME Colour Gel Paste Cupcake Decorating Rainbow Cake Colours 6 Set Kit https://www.amazon.co.uk/dp/B01JP6E14A/ref=cmswwrcppapiii_.GDuCbNQYMSX2

I would use gel rather than liquid

I've never opened this board before and came on to ask exactly this. I've just made two out of four layers and they're shite. The green one has faded to ordinary sponge colour and the red one, which even in the batter was only purple looks like ordinary chocolate sponge.

Have to do other two layers tomorrow night. No opportunity to buy more colouring so I assume there's no chance the blue and pink layers will stay any brighter however much I pour In?

Lakeland has a kit you just add egg and milk to I think. Bright colours and no faffing.

Gel colour: the regular liquid stuff you get from supermarkets will either not be bright enough or you'll add so much it will throw your dry/wet ingredient ratio

Yes gel colours.

I've not done a rainbow, but successfully done a two colour cake with the Wilton colours. I buy them from Amazon as a set.

I use Wilton gels.... the colour you get it great... I have the pastels and the rainbow sets... definitely use gels not liquids x

Yep you definitely have to use gels to get the vivid colours.

Sainsburys do a kit,very vibrant colours, no purple though.

I always use Wilton gels...colour comes out really vibrant

Bugger. Not sure I can fix this in time. Fingers crossed for the Sainsbury's at the top end of Tottenham Court Road coming good for me tomorrow!

Thanks everyone for the info.

Wilton gels worked really well for me

That looks fantastic!

Just update, I ordered these ones https://www.amazon.co.uk/dp/B01M6YDGMI?ref=pee31879112487648611302EEDDEdtt1

And it turned out really well. You can't see brilliantly in this photo as there were coloured lights in the room but you can see that the colours were vivid.

That looks brilliant - nice strong colours

Thanks for the gel tips. Turned out pretty well!

Wilton colours definitely.