[Tex/LaTex] Setting background colour with tikzposter

Question

I'm using tikzposter for the first time. Looking at the documentation (http://ctan.mirrors.hoobly.com/graphics/pgf/contrib/tikzposter/tikzposter.pdf), it seems it should be simple to set the background colour for the poster with \colorlet{backgroundcolor}{white}. However, it stays the same colour as the chosen theme (whereas the other settings all work fine). I guess there's some clash but I can't figure out what it is…

This is my code

\documentclass[25pt, a0paper, portrait]{tikzposter}
\usepackage[utf8]{inputenc}
\usepackage{color}

\title{Tikz Poster Example}
\author{ShareLaTeX Team}
\date{\today}
\institute{ShareLaTeX Institute}
\titlegraphic{\includegraphics[width=10cm]{logo1.pdf}}

\makeatletter
\renewcommand\TP@maketitle{%
 \begin{minipage}[b]{0.3\linewidth}
       \includegraphics[width=0.6\textwidth]{logo2.pdf}\\
       \normalsize \text{university}\\
       \normalsize \text{text}\\
       \end{minipage}%
\hfill
   \begin{minipage}[b]{0.5\linewidth}
        \centering
        \color{Black}
        {\bfseries \Huge \sc \@title \par}
        \vspace*{0.5em}
        {\huge \@author \par}
        \vspace*{0.5em}
        {\LARGE \@institute}
    \end{minipage}%
    \hfill
        \begin{minipage}[b]{0.2\linewidth}
           \begin{flushright}
           \@titlegraphic
           \end{flushright}
        \end{minipage}
    }
    \makeatother

\usepackage{blindtext}
\usepackage{comment}

\usetheme{Basic}

\begin{document}

\colorlet{backgroundcolor}{white}
\colorlet{framecolor}{black}
\colorlet{blocktitlebgcolor}{green}
\colorlet{blockbodybgcolor}{yellow}

\maketitle


 \begin{columns}
    \column{0.4}
      {
   \colorlet{blocktitlebgcolor}{cyan!25!green} 
    \block{BlocktitleB}{\lipsum[2]}
     }
\block{More text}{Text and more text}

\column{0.6}
\block{Something else}{Here, \blindtext \vspace{4cm}}
\note[
    targetoffsetx=-9cm, 
    targetoffsety=-6.5cm, 
    width=0.5\linewidth
    ]
    {e-mail \texttt{sharelatex@sharelatex.com}}
 \end{columns}

\begin{columns}
    \column{0.5}
    \block{A figure}
    {
        \begin{tikzfigure}
             \includegraphics[width=0.4\textwidth]{images/lion-logo.png}
        \end{tikzfigure}
     }
     \column{0.5}
    \block{Description of the figure}{\blindtext}
\end{columns}


\end{document}

Answer 1

You need to define \colorlet{backgroundcolor}{white} before \begin{document}. I think the background is drawn at \begin{document}, so redefining the backgroundcolor after \begin{document} has no effect, because the background is already created.

\documentclass{tikzposter}

\colorlet{backgroundcolor}{white} % before \begin{document}
\begin{document}

\end{document}