diff --git a/scan_explorer_service/manifest_factory.py b/scan_explorer_service/manifest_factory.py
index 2f76eb1..6fa313e 100644
--- a/scan_explorer_service/manifest_factory.py
+++ b/scan_explorer_service/manifest_factory.py
@@ -58,7 +58,6 @@ def get_or_create_canvas(self, page: Page):
         annotation.on = canvas.id
         canvas.add_annotation(annotation)
         canvas_dict[page.id] = canvas
-
         return canvas
 
     def create_image_annotation(self, page: Page):
diff --git a/scan_explorer_service/models.py b/scan_explorer_service/models.py
index 72a16d9..e0487bf 100644
--- a/scan_explorer_service/models.py
+++ b/scan_explorer_service/models.py
@@ -156,22 +156,25 @@ def image_url(self):
     @property
     def image_path(self):
         separator = current_app.config.get('IMAGE_API_SLASH_SUB', '%2F')
-        image_path = separator.join(self.image_path_basic) 
+        image_path = separator.join(self.image_path_basic[0]) 
         if self.color_type != PageColor.BW:
             image_path += '.tif'
         return image_path 
     
     @property
     def image_path_basic(self):
+        image_format = ''
         image_path = [self.collection.type, self.collection.journal, self.collection.volume]
         image_path = [item.replace('.', '_') for item in image_path]
         image_path = ['bitmaps'] + image_path + ['600', self.name]
-        
-        return image_path 
+        if self.color_type != PageColor.BW:
+            image_format = '.tif'
+        return image_path, image_format
 
     @property
     def thumbnail_url(self):
-        return f'{self.image_url}/square/480,480/0/{self.image_color_quality}.jpg'
+        url = f'{self.image_url}/square/480,480/0/{self.image_color_quality}.jpg'
+        return url
 
     @property
     def image_color_quality(self):
diff --git a/scan_explorer_service/open_search.py b/scan_explorer_service/open_search.py
index 85e7220..2fad6b3 100644
--- a/scan_explorer_service/open_search.py
+++ b/scan_explorer_service/open_search.py
@@ -112,6 +112,7 @@ def set_page_search_fields(query: dict) -> dict:
     return query
 
 def page_os_search(qs: str, page, limit, sort):
+    qs = qs.replace("&", "+")
     query = create_query_string_query(qs)
     query = set_page_search_fields(query)
     from_number = (page - 1) * limit
@@ -143,6 +144,7 @@ def page_ocr_os_search(collection_id: str, page_number:int):
     return es_result
 
 def aggregate_search(qs: str, aggregate_field, page, limit, sort):
+    qs = qs.replace("&", "+")
     query = create_query_string_query(qs)
     query = append_aggregate(query, aggregate_field, page, limit, sort)
     es_result = es_search(query)
diff --git a/scan_explorer_service/tests/test_proxy.py b/scan_explorer_service/tests/test_proxy.py
index fcc869a..052c15a 100644
--- a/scan_explorer_service/tests/test_proxy.py
+++ b/scan_explorer_service/tests/test_proxy.py
@@ -167,7 +167,6 @@ def test_fetch_object(self, mock_read_object_s3):
 
     @patch('scan_explorer_service.views.image_proxy.fetch_object')
     def test_pdf_save_success_article(self, mock_fetch_object):
-        # mock_read_object_s3.return_value = b'my_image_name'
         mock_fetch_object.return_value = b'my_image_name'
 
         data = {
diff --git a/scan_explorer_service/tests/test_search_utils.py b/scan_explorer_service/tests/test_search_utils.py
index 6265192..adf77da 100644
--- a/scan_explorer_service/tests/test_search_utils.py
+++ b/scan_explorer_service/tests/test_search_utils.py
@@ -37,6 +37,12 @@ def test_parse_query(self):
         final_query, _ = parse_query_string('PageColor:grAYsCaLe')
         self.assertEqual(final_query, 'page_color:Grayscale')
 
+        final_query, _ = parse_query_string('PageColor:BW')
+        self.assertEqual(final_query, 'page_color:BW')
+
+        final_query, _ = parse_query_string('PageColor:cOlor')
+        self.assertEqual(final_query, 'page_color:Color')
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/scan_explorer_service/utils/s3_utils.py b/scan_explorer_service/utils/s3_utils.py
index 2cffd65..c32f257 100644
--- a/scan_explorer_service/utils/s3_utils.py
+++ b/scan_explorer_service/utils/s3_utils.py
@@ -24,7 +24,7 @@ def write_object_s3(self, file_bytes, object_name):
         try:
             response = self.bucket.put_object(Body=file_bytes, Key=object_name)
         except (ClientError, ParamValidationError) as e:
-            current_app.logger.info.exception(e)
+            current_app.logger.exception(f"Error writing object {object_name}: {str(e)}")
             raise e
         return response.e_tag
 
@@ -35,8 +35,8 @@ def read_object_s3(self, object_name):
                 s3_obj.seek(0)
                 s3_file = s3_obj.read()
                 return s3_file
-        except (ClientError, ParamValidationError) as e:
-            current_app.logger.exception(e)
-            raise e
+        except Exception as e:
+            current_app.logger.exception(f"Unexpected error reading object {object_name}: {str(e)}")
+            raise
 
 
diff --git a/scan_explorer_service/utils/search_utils.py b/scan_explorer_service/utils/search_utils.py
index 439ffc9..3049657 100644
--- a/scan_explorer_service/utils/search_utils.py
+++ b/scan_explorer_service/utils/search_utils.py
@@ -53,8 +53,11 @@ class OrderOptions(str, enum.Enum):
 
 def parse_query_args(args):
     qs = re.sub(':\s*', ':', args.get('q', '', str))
+
     qs, qs_dict = parse_query_string(qs)
 
+
+
     page = args.get('page', 1, int)
     limit = args.get('limit', 10, int)
     sort_raw = args.get('sort')
@@ -73,7 +76,7 @@ def parse_query_string(qs):
         qs_only_free = qs_only_free.replace(kv, "")
         if len(kv_arr) == 2:
             qs_dict[kv_arr[0].lower()] = kv_arr[1].strip()
-            #If the option have qutoes we remove them from the free. Previous removal would than have failed
+            #If the option have quotes we remove them from the free. Previous removal would than have failed
             alt_kv = kv_arr[0] + ':"' + kv_arr[1] + '"'
             qs_only_free = qs_only_free.replace(alt_kv, '')
 
@@ -87,10 +90,9 @@ def parse_query_string(qs):
         #Translate input on the keys to the dedicated OS columns
         insensitive_replace = re.compile(re.escape(key), re.IGNORECASE)
         qs = insensitive_replace.sub(query_translations[key.lower()], qs)
-
-        insensitive_replace = re.compile(re.escape(qs_dict[key]), re.IGNORECASE)
+        # To ensure only the strings after the colon are replaced and no partial replacements are made 
+        insensitive_replace = re.compile(r'(?<=:)\b' + re.escape(qs_dict[key]) + r'\b', re.IGNORECASE)
         qs = insensitive_replace.sub(qs_dict[key], qs)
-
     return qs, qs_dict
 
 def parse_sorting_option(sort_input: str):
diff --git a/scan_explorer_service/views/image_proxy.py b/scan_explorer_service/views/image_proxy.py
index e15b310..3beb58f 100644
--- a/scan_explorer_service/views/image_proxy.py
+++ b/scan_explorer_service/views/image_proxy.py
@@ -1,5 +1,5 @@
 from typing import Union
-from flask import Blueprint, Response, current_app, request, stream_with_context, jsonify
+from flask import Blueprint, Response, current_app, request, stream_with_context, jsonify, send_file
 from flask_discoverer import advertise
 from urllib import parse as urlparse
 import img2pdf
@@ -9,6 +9,9 @@
 from scan_explorer_service.utils.db_utils import item_thumbnail
 from scan_explorer_service.utils.s3_utils import S3Provider
 from scan_explorer_service.utils.utils import url_for_proxy
+import re
+import io 
+import sys
 
 bp_proxy = Blueprint('proxy', __name__, url_prefix='/image')
 
@@ -23,9 +26,9 @@ def image_proxy(path):
     req_headers['X-Forwarded-Host'] = current_app.config.get('PROXY_SERVER')
     req_headers['X-Forwarded-Path'] = current_app.config.get('PROXY_PREFIX').rstrip('/') + '/image'
 
-    r = requests.request(request.method, req_url, params=request.args, stream=True,
-                         headers=req_headers, allow_redirects=False, data=request.form)
-
+    encoded_url = re.sub(r"[+&]", "%2B", req_url)
+    r = requests.request(request.method, encoded_url, params=request.args, stream=True,
+                         headers=req_headers, allow_redirects=False, data=request.form)      
     excluded_headers = ['content-encoding','content-length', 'transfer-encoding', 'connection']
     headers = [(name, value) for (name, value) in r.headers.items() if name.lower() not in excluded_headers]
 
@@ -41,13 +44,14 @@ def generate():
 def image_proxy_thumbnail():
     """Helper to generate the correct url for a thumbnail given an ID and type"""
     try:
-        id = request.args.get('id')
+        id = request.args.get('id').replace(" ", "+")
         type = request.args.get('type')
         with current_app.session_scope() as session:
             thumbnail_path = item_thumbnail(session, id, type)
             path = urlparse.urlparse(thumbnail_path).path
             
             remove = urlparse.urlparse(url_for_proxy('proxy.image_proxy', path='')).path
+            
             path = path.replace(remove, '')
             
             return image_proxy(path)
@@ -75,61 +79,72 @@ def get_pages(item, session, page_start, page_end, page_limit):
         query = session.query(Page).filter(Page.collection_id == item.id, 
             Page.volume_running_page_num >= page_start, 
             Page.volume_running_page_num <= page_end).order_by(Page.volume_running_page_num).limit(page_limit)
-    current_app.logger.info(f"Got pages {page_start}-{page_end}: {query}") 
     return query 
 
 
 @stream_with_context
 def fetch_images(session, item, page_start, page_end, page_limit, memory_limit):
-        n_pages = 0
-        memory_sum = 0
-        query = get_pages(item, session, page_start, page_end, page_limit)
-        for page in query.all():
-            
-            n_pages += 1
-            
-            current_app.logger.debug(f"Generating image for page: {n_pages}") 
-            current_app.logger.debug(f'Id: {page.id}, Volume_page: {page.volume_running_page_num}, memory: {memory_sum}')
-            if n_pages > page_limit:
-                break
-            if memory_sum > memory_limit:
-                current_app.logger.error(f"Memory limit reached: {memory_sum} > {memory_limit}") 
-                break
-         
-            object_name = '/'.join(page.image_path_basic)
-            current_app.logger.debug(f"Image path: {object_name}")
-            im_data = fetch_object(object_name, 'AWS_BUCKET_NAME_IMAGE')
+    n_pages = 0
+    memory_sum = 0
+    query = get_pages(item, session, page_start, page_end, page_limit)
+    for page in query.all():
+        
+        n_pages += 1
+        
+        current_app.logger.debug(f"Generating image for page: {n_pages}") 
+        if n_pages > page_limit:
+            break
+        if memory_sum > memory_limit:
+            current_app.logger.error(f"Memory limit reached: {memory_sum} > {memory_limit}") 
+            break
+        image_path, format = page.image_path_basic
+        object_name = '/'.join(image_path)
+        object_name += format
+
+        im_data = fetch_object(object_name, 'AWS_BUCKET_NAME_IMAGE')
+        memory_sum += sys.getsizeof(im_data)
 
-            yield im_data
+        yield im_data
 
 
 def fetch_object(object_name, bucket_name):
     file_content = S3Provider(current_app.config, bucket_name).read_object_s3(object_name)
-    current_app.logger.info(f"Successfully fetched object from S3 bucket: {object_name}")
+    if not file_content:
+        current_app.logger.error(f"Failed to fetch content for {object_name}. File might be empty.")
+        raise ValueError(f"File content is empty for {object_name}")
     return file_content
 
 
-def fetch_article(item):
+def fetch_article(item, memory_limit):
     try:
-        current_app.logger.info(f"Item is an article: {item.id}")
         object_name = f'{item.id}.pdf'.lower()
         full_path = f'pdfs/{object_name}'
         file_content = fetch_object(full_path, 'AWS_BUCKET_NAME_PDF')
-        response = Response(file_content, mimetype='application/pdf')
-        response.headers['Content-Disposition'] = f'attachment; filename="{object_name}"'
-        return response
+
+        if len(file_content) > memory_limit:
+            current_app.logger.error(f"Memory limit reached: {len(file_content)} > {memory_limit}") 
+
+        file_stream = io.BytesIO(file_content)
+        file_stream.seek(0)
+        return send_file(
+            file_stream,
+            as_attachment=True,
+            attachment_filename=object_name,
+            mimetype='application/pdf'
+        )
     except Exception as e:
         current_app.logger.exception(f"Failed to get PDF using fallback method for {object_name}: {str(e)}")
         
        
 def generate_pdf(item, session, page_start, page_end, page_limit, memory_limit): 
     if isinstance(item, Article):
-        response = fetch_article(item)
+        response = fetch_article(item, memory_limit)
         if response:
             return response
         else:
+            current_app.logger.debug(f"Response fetch article was empty")
             page_end = page_limit
-
+    current_app.logger.debug(f"Article is not an article or fetch article failed.")
     return Response(img2pdf.convert([im for im in fetch_images(session, item, page_start, page_end, page_limit, memory_limit)]), mimetype='application/pdf')
 
                  
@@ -147,7 +162,7 @@ def pdf_save():
         with current_app.session_scope() as session:
             
             item = get_item(session, id) 
-            current_app.logger.info(f"Item retrieved successfully: {item.id}")
+            current_app.logger.debug(f"Item retrieved successfully: {item.id}")
 
             response = generate_pdf(item, session, page_start, page_end, page_limit, memory_limit)
             return response 
diff --git a/scan_explorer_service/views/manifest.py b/scan_explorer_service/views/manifest.py
index adfe0fe..b1dd1eb 100644
--- a/scan_explorer_service/views/manifest.py
+++ b/scan_explorer_service/views/manifest.py
@@ -35,7 +35,7 @@ def get_manifest(id: str):
             manifest = manifest_factory.create_manifest(item)
             search_url = url_for_proxy('manifest.search', id=id)
             manifest_factory.add_search_service(manifest, search_url)
-
+            
             return manifest.toJSON(top=True)
         else:
             return jsonify(exception='Article not found'), 404
diff --git a/scan_explorer_service/views/metadata.py b/scan_explorer_service/views/metadata.py
index 5721be8..8d610ab 100644
--- a/scan_explorer_service/views/metadata.py
+++ b/scan_explorer_service/views/metadata.py
@@ -22,17 +22,16 @@ def article_extra(bibcode: str):
     
     if auth_token and ads_search_service:
         try:
-            params = {'q': f'bibcode:{bibcode}', 'fl':'title,author'}   
+            params = {'q': f'bibcode:{bibcode}', 'fl':'title,author'} 
             headers = {'Authorization': f'Bearer {auth_token}'}
             response = requests.get(ads_search_service, params, headers=headers).json()
             docs = response.get('response').get('docs')
-
             if docs:
                 return docs[0]
-        except:
+            else: 
+                return jsonify(message='No article found'), 404
+        except Exception as e:
             return jsonify(message='Failed to retrieve external ADS article metadata'), 500
-        
-        
     return {}
 
 @advertise(scopes=['api'], rate_limit=[300, 3600*24])
@@ -141,7 +140,7 @@ def article_search():
             page_count = page_os_search(qs, page, limit, sort)['hits']['total']['value']
         return jsonify(serialize_os_article_result(result, page, limit, text_query, collection_count, page_count))
     except Exception as e:
-        current_app.logger.error(f"{e}")
+        current_app.logger.exception(f"An exception has occurred: {e}")
         return jsonify(message=str(e), type=ApiErrors.SearchError.value), 400