[Tex/LaTex] Transparent text: what alternatives to the transparent package

Question

I want to write some text with a semi-transparent color.

I have tried the transparent package but it seems to be in conflict with some other package. In a MWE, it works BUT in my real case, it does not work (I load a lot of packages)

So, my question is: How to make a text semi-transparent, without the transparent package?

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Remark

\tikz\node[opacity=0.5]{Hello}; does the work but it adds some space after Hello.

If you think of another possible solution, I would be interested.

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PS:
Here is image of what I want to achieve.

PPS: I need a transparent color and not a plain gray.

Answer 1

EDITED to use Daniel's comment to make the undertext transparent, using a tikz node. The OP mentions in his/her comment to Daniel the presence of "some space after Hello", but I'm not sure how that applies to this solution (since the \stackunder is centered).

EDITED to take OP's suggestions. However, I would note that the horizontal alignment of this solution is impervious to inner sep, since the underset is automatically centered. However, the inner sep will slightly alter the vertical position of the underset.

\documentclass{article}
\usepackage{stackengine,tikz}
\begin{document}
\[
\pagecolor{blue!10}
\stackunder[8pt]{$\displaystyle \int_0^1 f(t)dt$}{%
  \tikz\node[inner sep=0pt, opacity=0.5]{Hello};}
\]
\end{document}