diff --git a/src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs b/src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs
index 9821cb34..5a3be587 100644
--- a/src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs
+++ b/src/UglyToad.PdfPig/Graphics/ContentStreamProcessor.cs
@@ -16,6 +16,7 @@
     {
         private readonly IResourceStore resourceStore;
         private readonly UserSpaceUnit userSpaceUnit;
+        private readonly bool isLenientParsing;
 
         private Stack<CurrentGraphicsState> graphicsStack = new Stack<CurrentGraphicsState>();
 
@@ -25,10 +26,11 @@
         
         public List<Letter> Letters = new List<Letter>();
 
-        public ContentStreamProcessor(PdfRectangle cropBox, IResourceStore resourceStore, UserSpaceUnit userSpaceUnit)
+        public ContentStreamProcessor(PdfRectangle cropBox, IResourceStore resourceStore, UserSpaceUnit userSpaceUnit, bool isLenientParsing)
         {
             this.resourceStore = resourceStore;
             this.userSpaceUnit = userSpaceUnit;
+            this.isLenientParsing = isLenientParsing;
             graphicsStack.Push(new CurrentGraphicsState());
         }
 
@@ -104,7 +106,12 @@
             {
                 var code = font.ReadCharacterCode(bytes, out int codeLength);
 
-                font.TryGetUnicode(code, out var unicode);
+                var foundUnicode = font.TryGetUnicode(code, out var unicode);
+
+                if (!foundUnicode && !isLenientParsing)
+                {
+                    throw new InvalidOperationException($"We could not find the corresponding character with code {code} in font {font.Name}.");
+                }
 
                 var wordSpacing = 0m;
                 if (code == ' ' && codeLength == 1)
diff --git a/src/UglyToad.PdfPig/Parser/PageFactory.cs b/src/UglyToad.PdfPig/Parser/PageFactory.cs
index 79d28b42..ad669f26 100644
--- a/src/UglyToad.PdfPig/Parser/PageFactory.cs
+++ b/src/UglyToad.PdfPig/Parser/PageFactory.cs
@@ -67,7 +67,7 @@
 
                 var bytes = contentStream.Decode(filterProvider);
 
-                content = GetContent(bytes, cropBox, userSpaceUnit);
+                content = GetContent(bytes, cropBox, userSpaceUnit, isLenientParsing);
             }
             else if (contents is COSArray arr)
             {
@@ -91,7 +91,7 @@
                     bytes.AddRange(contentStream.Decode(filterProvider));
                 }
 
-                content = GetContent(bytes, cropBox, userSpaceUnit);
+                content = GetContent(bytes, cropBox, userSpaceUnit, isLenientParsing);
             }
 
             var page = new Page(number, mediaBox, cropBox, content);
@@ -99,7 +99,7 @@
             return page;
         }
 
-        private PageContent GetContent(IReadOnlyList<byte> contentBytes, CropBox cropBox, UserSpaceUnit userSpaceUnit)
+        private PageContent GetContent(IReadOnlyList<byte> contentBytes, CropBox cropBox, UserSpaceUnit userSpaceUnit, bool isLenientParsing)
         {
             if (Debugger.IsAttached)
             {
@@ -108,7 +108,7 @@
 
             var operations = pageContentParser.Parse(new ByteArrayInputBytes(contentBytes));
 
-            var context = new ContentStreamProcessor(cropBox.Bounds, resourceStore, userSpaceUnit);
+            var context = new ContentStreamProcessor(cropBox.Bounds, resourceStore, userSpaceUnit, isLenientParsing);
 
             return context.Process(operations);
         }