Change code in PURE theme

Hello, there is this beautiful free theme I have found ‘Pure’. https://www.gt3themes.com/wordpress-themes/pure/ its quite powerfull with many options. What I would like to do is to change a small thing how the samples in portfolio are shown. Here when you point a cursor over the picture it would zoom in. I would like to change it to a greish effect that I saw in this ‘Spun’ theme. https://spundemo.wordpress.com/ Is there an easy way to change the code from one theme to another? Here they talk about the code for spun: https://www.ads-software.com/support/topic/remove-grey-scale?replies=10
Thanks.