From 5e1be758775542796016c5e3cd23c77908cf14ee Mon Sep 17 00:00:00 2001
From: Pey Lian Lim <lim@stsci.edu>
Date: Tue, 13 Sep 2016 16:55:26 -0400
Subject: [PATCH] Do not discard neg throughput, to be consistent with ASTROLIB
 PYSYNPHOT. [skip ci]

---
 synphot/spectrum.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/synphot/spectrum.py b/synphot/spectrum.py
index 59300836..75103fb0 100644
--- a/synphot/spectrum.py
+++ b/synphot/spectrum.py
@@ -1737,7 +1737,7 @@ def from_file(cls, filename, **kwargs):
 
         header, wavelengths, throughput = specio.read_spec(filename, **kwargs)
         return cls(Empirical1D, points=wavelengths, lookup_table=throughput,
-                   meta={'header': header})
+                   keep_neg=True, meta={'header': header})
 
     @classmethod
     def from_filter(cls, filtername, **kwargs):