# Color transparency for conditional\_effects in brms

**URL:** <https://discourse.mc-stan.org/t/color-transparency-for-conditional-effects-in-brms/19715>\
**Category:** brms\
**Created:** [December 9, 2020, 4:23pm UTC](https://discourse.mc-stan.org/t/color-transparency-for-conditional-effects-in-brms/19715 "2020-12-09T16:23:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![petrovska](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/petrovska/32/8375_2.png) [@petrovska](https://discourse.mc-stan.org/u/petrovska)\
**Post date:** [December 9, 2020, 4:23pm UTC](https://discourse.mc-stan.org/t/color-transparency-for-conditional-effects-in-brms/19715/1 "2020-12-09T16:23:27Z")

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Hello community,

Could someone advise if there is a way to change colours transparency in conditional\_effects plot in brms package. So far, I cannot override default alpha by scale\_alpha\_manual. Any ideas?

```
conditions1=data.frame(species.m = c("Acer platanoides","Acer pseudoplatanus","Fagus sylvatica"), status.p=c("alive"))

plot(conditional_effects(fit3, method = "fitted", effects=c("ba_m2.c:species.p"), 
  conditions=conditions1, mean=TRUE), plot = T, points=T, rug=T, facet_args=nlist(facets="species.m"))[[1]]+
  theme(legend.position = "top")+scale_y_continuous(breaks=seq(0,7, by=1))+coord_cartesian(y=c(0,7))+
  scale_color_manual(values = c("Acer platanoides"="darkblue","Acer pseudoplatanus"="mediumslateblue","Fagus sylvatica"="deeppink3","Ulmus glabra"="yellow"))+
  scale_fill_manual(values = c("Acer platanoides"="darkblue","Acer pseudoplatanus"="mediumslateblue","Fagus sylvatica"="deeppink3","Ulmus glabra"="yellow"))+
  scale_alpha_manual(values = c("Acer platanoides"=0.1,"Acer pseudoplatanus"=0.1,"Fagus sylvatica"=0.1,"Ulmus glabra"=0.1))

```

Operating System: Windows 10  
Interface Version: brms 2.14.0  
Compiler/Toolkit:

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**Author:** ![jonah](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/jonah/32/200_2.png) [@jonah](https://discourse.mc-stan.org/u/jonah)\
**Post date:** [December 9, 2020, 5:37pm UTC](https://discourse.mc-stan.org/t/color-transparency-for-conditional-effects-in-brms/19715/2 "2020-12-09T17:37:37Z")

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The plot method for conditional effects has a bunch of arguments passed to ggplot2

```
  line_args = list(),
  cat_args = list(),
  errorbar_args = list(),
  surface_args = list(),
  spaghetti_args = list(),
  point_args = list(),
  rug_args = list(),

```

and I think you should be able to pass `alpha` in those lists. Does that let make the plot you’re looking for?

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**Author:** ![petrovska](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/petrovska/32/8375_2.png) [@petrovska](https://discourse.mc-stan.org/u/petrovska)\
**Post date:** [December 9, 2020, 7:22pm UTC](https://discourse.mc-stan.org/t/color-transparency-for-conditional-effects-in-brms/19715/3 "2020-12-09T19:22:51Z")

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Yes, it works! Thank you so much, you save me hours!

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**Author:** ![jonah](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/jonah/32/200_2.png) [@jonah](https://discourse.mc-stan.org/u/jonah)\
**Post date:** [December 9, 2020, 8:56pm UTC](https://discourse.mc-stan.org/t/color-transparency-for-conditional-effects-in-brms/19715/4 "2020-12-09T20:56:16Z")

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Great, glad that worked!